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1/*
2** 2001 September 15
3**
4** The author disclaims copyright to this source code. In place of
5** a legal notice, here is a blessing:
6**
7** May you do good and not evil.
8** May you find forgiveness for yourself and forgive others.
9** May you share freely, never taking more than you give.
10**
11*************************************************************************
12** This file contains C code routines that are called by the parser
13** to handle SELECT statements in SQLite.
14**
15** $Id: select.c,v 1.351 2007/06/15 15:31:50 drh Exp $
16*/
17#include "sqliteInt.h"
18
19
20/*
21** Delete all the content of a Select structure but do not deallocate
22** the select structure itself.
23*/
24static void clearSelect(Select *p){
25 sqlite3ExprListDelete(p->pEList);
26 sqlite3SrcListDelete(p->pSrc);
27 sqlite3ExprDelete(p->pWhere);
28 sqlite3ExprListDelete(p->pGroupBy);
29 sqlite3ExprDelete(p->pHaving);
30 sqlite3ExprListDelete(p->pOrderBy);
31 sqlite3SelectDelete(p->pPrior);
32 sqlite3ExprDelete(p->pLimit);
33 sqlite3ExprDelete(p->pOffset);
34}
35
36
37/*
38** Allocate a new Select structure and return a pointer to that
39** structure.
40*/
41Select *sqlite3SelectNew(
42 ExprList *pEList, /* which columns to include in the result */
43 SrcList *pSrc, /* the FROM clause -- which tables to scan */
44 Expr *pWhere, /* the WHERE clause */
45 ExprList *pGroupBy, /* the GROUP BY clause */
46 Expr *pHaving, /* the HAVING clause */
47 ExprList *pOrderBy, /* the ORDER BY clause */
48 int isDistinct, /* true if the DISTINCT keyword is present */
49 Expr *pLimit, /* LIMIT value. NULL means not used */
50 Expr *pOffset /* OFFSET value. NULL means no offset */
51){
52 Select *pNew;
53 Select standin;
54 pNew = sqliteMalloc( sizeof(*pNew) );
55 assert( !pOffset || pLimit ); /* Can't have OFFSET without LIMIT. */
56 if( pNew==0 ){
57 pNew = &standin;
58 memset(pNew, 0, sizeof(*pNew));
59 }
60 if( pEList==0 ){
61 pEList = sqlite3ExprListAppend(0, sqlite3Expr(TK_ALL,0,0,0), 0);
62 }
63 pNew->pEList = pEList;
64 pNew->pSrc = pSrc;
65 pNew->pWhere = pWhere;
66 pNew->pGroupBy = pGroupBy;
67 pNew->pHaving = pHaving;
68 pNew->pOrderBy = pOrderBy;
69 pNew->isDistinct = isDistinct;
70 pNew->op = TK_SELECT;
71 assert( pOffset==0 || pLimit!=0 );
72 pNew->pLimit = pLimit;
73 pNew->pOffset = pOffset;
74 pNew->iLimit = -1;
75 pNew->iOffset = -1;
76 pNew->addrOpenEphm[0] = -1;
77 pNew->addrOpenEphm[1] = -1;
78 pNew->addrOpenEphm[2] = -1;
79 if( pNew==&standin) {
80 clearSelect(pNew);
81 pNew = 0;
82 }
83 return pNew;
84}
85
86/*
87** Delete the given Select structure and all of its substructures.
88*/
89void sqlite3SelectDelete(Select *p){
90 if( p ){
91 clearSelect(p);
92 sqliteFree(p);
93 }
94}
95
96/*
97** Given 1 to 3 identifiers preceeding the JOIN keyword, determine the
98** type of join. Return an integer constant that expresses that type
99** in terms of the following bit values:
100**
101** JT_INNER
102** JT_CROSS
103** JT_OUTER
104** JT_NATURAL
105** JT_LEFT
106** JT_RIGHT
107**
108** A full outer join is the combination of JT_LEFT and JT_RIGHT.
109**
110** If an illegal or unsupported join type is seen, then still return
111** a join type, but put an error in the pParse structure.
112*/
113int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *pC){
114 int jointype = 0;
115 Token *apAll[3];
116 Token *p;
117 static const struct {
118 const char zKeyword[8];
119 u8 nChar;
120 u8 code;
121 } keywords[] = {
122 { "natural", 7, JT_NATURAL },
123 { "left", 4, JT_LEFT|JT_OUTER },
124 { "right", 5, JT_RIGHT|JT_OUTER },
125 { "full", 4, JT_LEFT|JT_RIGHT|JT_OUTER },
126 { "outer", 5, JT_OUTER },
127 { "inner", 5, JT_INNER },
128 { "cross", 5, JT_INNER|JT_CROSS },
129 };
130 int i, j;
131 apAll[0] = pA;
132 apAll[1] = pB;
133 apAll[2] = pC;
134 for(i=0; i<3 && apAll[i]; i++){
135 p = apAll[i];
136 for(j=0; j<sizeof(keywords)/sizeof(keywords[0]); j++){
137 if( p->n==keywords[j].nChar
138 && sqlite3StrNICmp((char*)p->z, keywords[j].zKeyword, p->n)==0 ){
139 jointype |= keywords[j].code;
140 break;
141 }
142 }
143 if( j>=sizeof(keywords)/sizeof(keywords[0]) ){
144 jointype |= JT_ERROR;
145 break;
146 }
147 }
148 if(
149 (jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) ||
150 (jointype & JT_ERROR)!=0
151 ){
152 const char *zSp1 = " ";
153 const char *zSp2 = " ";
154 if( pB==0 ){ zSp1++; }
155 if( pC==0 ){ zSp2++; }
156 sqlite3ErrorMsg(pParse, "unknown or unsupported join type: "
157 "%T%s%T%s%T", pA, zSp1, pB, zSp2, pC);
158 jointype = JT_INNER;
159 }else if( jointype & JT_RIGHT ){
160 sqlite3ErrorMsg(pParse,
161 "RIGHT and FULL OUTER JOINs are not currently supported");
162 jointype = JT_INNER;
163 }
164 return jointype;
165}
166
167/*
168** Return the index of a column in a table. Return -1 if the column
169** is not contained in the table.
170*/
171static int columnIndex(Table *pTab, const char *zCol){
172 int i;
173 for(i=0; i<pTab->nCol; i++){
174 if( sqlite3StrICmp(pTab->aCol[i].zName, zCol)==0 ) return i;
175 }
176 return -1;
177}
178
179/*
180** Set the value of a token to a '\000'-terminated string.
181*/
182static void setToken(Token *p, const char *z){
183 p->z = (u8*)z;
184 p->n = z ? strlen(z) : 0;
185 p->dyn = 0;
186}
187
188/*
189** Create an expression node for an identifier with the name of zName
190*/
191Expr *sqlite3CreateIdExpr(const char *zName){
192 Token dummy;
193 setToken(&dummy, zName);
194 return sqlite3Expr(TK_ID, 0, 0, &dummy);
195}
196
197
198/*
199** Add a term to the WHERE expression in *ppExpr that requires the
200** zCol column to be equal in the two tables pTab1 and pTab2.
201*/
202static void addWhereTerm(
203 const char *zCol, /* Name of the column */
204 const Table *pTab1, /* First table */
205 const char *zAlias1, /* Alias for first table. May be NULL */
206 const Table *pTab2, /* Second table */
207 const char *zAlias2, /* Alias for second table. May be NULL */
208 int iRightJoinTable, /* VDBE cursor for the right table */
209 Expr **ppExpr /* Add the equality term to this expression */
210){
211 Expr *pE1a, *pE1b, *pE1c;
212 Expr *pE2a, *pE2b, *pE2c;
213 Expr *pE;
214
215 pE1a = sqlite3CreateIdExpr(zCol);
216 pE2a = sqlite3CreateIdExpr(zCol);
217 if( zAlias1==0 ){
218 zAlias1 = pTab1->zName;
219 }
220 pE1b = sqlite3CreateIdExpr(zAlias1);
221 if( zAlias2==0 ){
222 zAlias2 = pTab2->zName;
223 }
224 pE2b = sqlite3CreateIdExpr(zAlias2);
225 pE1c = sqlite3ExprOrFree(TK_DOT, pE1b, pE1a, 0);
226 pE2c = sqlite3ExprOrFree(TK_DOT, pE2b, pE2a, 0);
227 pE = sqlite3ExprOrFree(TK_EQ, pE1c, pE2c, 0);
228 if( pE ){
229 ExprSetProperty(pE, EP_FromJoin);
230 pE->iRightJoinTable = iRightJoinTable;
231 }
232 pE = sqlite3ExprAnd(*ppExpr, pE);
233 if( pE ){
234 *ppExpr = pE;
235 }
236}
237
238/*
239** Set the EP_FromJoin property on all terms of the given expression.
240** And set the Expr.iRightJoinTable to iTable for every term in the
241** expression.
242**
243** The EP_FromJoin property is used on terms of an expression to tell
244** the LEFT OUTER JOIN processing logic that this term is part of the
245** join restriction specified in the ON or USING clause and not a part
246** of the more general WHERE clause. These terms are moved over to the
247** WHERE clause during join processing but we need to remember that they
248** originated in the ON or USING clause.
249**
250** The Expr.iRightJoinTable tells the WHERE clause processing that the
251** expression depends on table iRightJoinTable even if that table is not
252** explicitly mentioned in the expression. That information is needed
253** for cases like this:
254**
255** SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.b AND t1.x=5
256**
257** The where clause needs to defer the handling of the t1.x=5
258** term until after the t2 loop of the join. In that way, a
259** NULL t2 row will be inserted whenever t1.x!=5. If we do not
260** defer the handling of t1.x=5, it will be processed immediately
261** after the t1 loop and rows with t1.x!=5 will never appear in
262** the output, which is incorrect.
263*/
264static void setJoinExpr(Expr *p, int iTable){
265 while( p ){
266 ExprSetProperty(p, EP_FromJoin);
267 p->iRightJoinTable = iTable;
268 setJoinExpr(p->pLeft, iTable);
269 p = p->pRight;
270 }
271}
272
273/*
274** This routine processes the join information for a SELECT statement.
275** ON and USING clauses are converted into extra terms of the WHERE clause.
276** NATURAL joins also create extra WHERE clause terms.
277**
278** The terms of a FROM clause are contained in the Select.pSrc structure.
279** The left most table is the first entry in Select.pSrc. The right-most
280** table is the last entry. The join operator is held in the entry to
281** the left. Thus entry 0 contains the join operator for the join between
282** entries 0 and 1. Any ON or USING clauses associated with the join are
283** also attached to the left entry.
284**
285** This routine returns the number of errors encountered.
286*/
287static int sqliteProcessJoin(Parse *pParse, Select *p){
288 SrcList *pSrc; /* All tables in the FROM clause */
289 int i, j; /* Loop counters */
290 struct SrcList_item *pLeft; /* Left table being joined */
291 struct SrcList_item *pRight; /* Right table being joined */
292
293 pSrc = p->pSrc;
294 pLeft = &pSrc->a[0];
295 pRight = &pLeft[1];
296 for(i=0; i<pSrc->nSrc-1; i++, pRight++, pLeft++){
297 Table *pLeftTab = pLeft->pTab;
298 Table *pRightTab = pRight->pTab;
299
300 if( pLeftTab==0 || pRightTab==0 ) continue;
301
302 /* When the NATURAL keyword is present, add WHERE clause terms for
303 ** every column that the two tables have in common.
304 */
305 if( pRight->jointype & JT_NATURAL ){
306 if( pRight->pOn || pRight->pUsing ){
307 sqlite3ErrorMsg(pParse, "a NATURAL join may not have "
308 "an ON or USING clause", 0);
309 return 1;
310 }
311 for(j=0; j<pLeftTab->nCol; j++){
312 char *zName = pLeftTab->aCol[j].zName;
313 if( columnIndex(pRightTab, zName)>=0 ){
314 addWhereTerm(zName, pLeftTab, pLeft->zAlias,
315 pRightTab, pRight->zAlias,
316 pRight->iCursor, &p->pWhere);
317
318 }
319 }
320 }
321
322 /* Disallow both ON and USING clauses in the same join
323 */
324 if( pRight->pOn && pRight->pUsing ){
325 sqlite3ErrorMsg(pParse, "cannot have both ON and USING "
326 "clauses in the same join");
327 return 1;
328 }
329
330 /* Add the ON clause to the end of the WHERE clause, connected by
331 ** an AND operator.
332 */
333 if( pRight->pOn ){
334 setJoinExpr(pRight->pOn, pRight->iCursor);
335 p->pWhere = sqlite3ExprAnd(p->pWhere, pRight->pOn);
336 pRight->pOn = 0;
337 }
338
339 /* Create extra terms on the WHERE clause for each column named
340 ** in the USING clause. Example: If the two tables to be joined are
341 ** A and B and the USING clause names X, Y, and Z, then add this
342 ** to the WHERE clause: A.X=B.X AND A.Y=B.Y AND A.Z=B.Z
343 ** Report an error if any column mentioned in the USING clause is
344 ** not contained in both tables to be joined.
345 */
346 if( pRight->pUsing ){
347 IdList *pList = pRight->pUsing;
348 for(j=0; j<pList->nId; j++){
349 char *zName = pList->a[j].zName;
350 if( columnIndex(pLeftTab, zName)<0 || columnIndex(pRightTab, zName)<0 ){
351 sqlite3ErrorMsg(pParse, "cannot join using column %s - column "
352 "not present in both tables", zName);
353 return 1;
354 }
355 addWhereTerm(zName, pLeftTab, pLeft->zAlias,
356 pRightTab, pRight->zAlias,
357 pRight->iCursor, &p->pWhere);
358 }
359 }
360 }
361 return 0;
362}
363
364/*
365** Insert code into "v" that will push the record on the top of the
366** stack into the sorter.
367*/
368static void pushOntoSorter(
369 Parse *pParse, /* Parser context */
370 ExprList *pOrderBy, /* The ORDER BY clause */
371 Select *pSelect /* The whole SELECT statement */
372){
373 Vdbe *v = pParse->pVdbe;
374 sqlite3ExprCodeExprList(pParse, pOrderBy);
375 sqlite3VdbeAddOp(v, OP_Sequence, pOrderBy->iECursor, 0);
376 sqlite3VdbeAddOp(v, OP_Pull, pOrderBy->nExpr + 1, 0);
377 sqlite3VdbeAddOp(v, OP_MakeRecord, pOrderBy->nExpr + 2, 0);
378 sqlite3VdbeAddOp(v, OP_IdxInsert, pOrderBy->iECursor, 0);
379 if( pSelect->iLimit>=0 ){
380 int addr1, addr2;
381 addr1 = sqlite3VdbeAddOp(v, OP_IfMemZero, pSelect->iLimit+1, 0);
382 sqlite3VdbeAddOp(v, OP_MemIncr, -1, pSelect->iLimit+1);
383 addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
384 sqlite3VdbeJumpHere(v, addr1);
385 sqlite3VdbeAddOp(v, OP_Last, pOrderBy->iECursor, 0);
386 sqlite3VdbeAddOp(v, OP_Delete, pOrderBy->iECursor, 0);
387 sqlite3VdbeJumpHere(v, addr2);
388 pSelect->iLimit = -1;
389 }
390}
391
392/*
393** Add code to implement the OFFSET
394*/
395static void codeOffset(
396 Vdbe *v, /* Generate code into this VM */
397 Select *p, /* The SELECT statement being coded */
398 int iContinue, /* Jump here to skip the current record */
399 int nPop /* Number of times to pop stack when jumping */
400){
401 if( p->iOffset>=0 && iContinue!=0 ){
402 int addr;
403 sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iOffset);
404 addr = sqlite3VdbeAddOp(v, OP_IfMemNeg, p->iOffset, 0);
405 if( nPop>0 ){
406 sqlite3VdbeAddOp(v, OP_Pop, nPop, 0);
407 }
408 sqlite3VdbeAddOp(v, OP_Goto, 0, iContinue);
409 VdbeComment((v, "# skip OFFSET records"));
410 sqlite3VdbeJumpHere(v, addr);
411 }
412}
413
414/*
415** Add code that will check to make sure the top N elements of the
416** stack are distinct. iTab is a sorting index that holds previously
417** seen combinations of the N values. A new entry is made in iTab
418** if the current N values are new.
419**
420** A jump to addrRepeat is made and the N+1 values are popped from the
421** stack if the top N elements are not distinct.
422*/
423static void codeDistinct(
424 Vdbe *v, /* Generate code into this VM */
425 int iTab, /* A sorting index used to test for distinctness */
426 int addrRepeat, /* Jump to here if not distinct */
427 int N /* The top N elements of the stack must be distinct */
428){
429 sqlite3VdbeAddOp(v, OP_MakeRecord, -N, 0);
430 sqlite3VdbeAddOp(v, OP_Distinct, iTab, sqlite3VdbeCurrentAddr(v)+3);
431 sqlite3VdbeAddOp(v, OP_Pop, N+1, 0);
432 sqlite3VdbeAddOp(v, OP_Goto, 0, addrRepeat);
433 VdbeComment((v, "# skip indistinct records"));
434 sqlite3VdbeAddOp(v, OP_IdxInsert, iTab, 0);
435}
436
437/*
438** Generate an error message when a SELECT is used within a subexpression
439** (example: "a IN (SELECT * FROM table)") but it has more than 1 result
440** column. We do this in a subroutine because the error occurs in multiple
441** places.
442*/
443static int checkForMultiColumnSelectError(Parse *pParse, int eDest, int nExpr){
444 if( nExpr>1 && (eDest==SRT_Mem || eDest==SRT_Set) ){
445 sqlite3ErrorMsg(pParse, "only a single result allowed for "
446 "a SELECT that is part of an expression");
447 return 1;
448 }else{
449 return 0;
450 }
451}
452
453/*
454** This routine generates the code for the inside of the inner loop
455** of a SELECT.
456**
457** If srcTab and nColumn are both zero, then the pEList expressions
458** are evaluated in order to get the data for this row. If nColumn>0
459** then data is pulled from srcTab and pEList is used only to get the
460** datatypes for each column.
461*/
462static int selectInnerLoop(
463 Parse *pParse, /* The parser context */
464 Select *p, /* The complete select statement being coded */
465 ExprList *pEList, /* List of values being extracted */
466 int srcTab, /* Pull data from this table */
467 int nColumn, /* Number of columns in the source table */
468 ExprList *pOrderBy, /* If not NULL, sort results using this key */
469 int distinct, /* If >=0, make sure results are distinct */
470 int eDest, /* How to dispose of the results */
471 int iParm, /* An argument to the disposal method */
472 int iContinue, /* Jump here to continue with next row */
473 int iBreak, /* Jump here to break out of the inner loop */
474 char *aff /* affinity string if eDest is SRT_Union */
475){
476 Vdbe *v = pParse->pVdbe;
477 int i;
478 int hasDistinct; /* True if the DISTINCT keyword is present */
479
480 if( v==0 ) return 0;
481 assert( pEList!=0 );
482
483 /* If there was a LIMIT clause on the SELECT statement, then do the check
484 ** to see if this row should be output.
485 */
486 hasDistinct = distinct>=0 && pEList->nExpr>0;
487 if( pOrderBy==0 && !hasDistinct ){
488 codeOffset(v, p, iContinue, 0);
489 }
490
491 /* Pull the requested columns.
492 */
493 if( nColumn>0 ){
494 for(i=0; i<nColumn; i++){
495 sqlite3VdbeAddOp(v, OP_Column, srcTab, i);
496 }
497 }else{
498 nColumn = pEList->nExpr;
499 sqlite3ExprCodeExprList(pParse, pEList);
500 }
501
502 /* If the DISTINCT keyword was present on the SELECT statement
503 ** and this row has been seen before, then do not make this row
504 ** part of the result.
505 */
506 if( hasDistinct ){
507 assert( pEList!=0 );
508 assert( pEList->nExpr==nColumn );
509 codeDistinct(v, distinct, iContinue, nColumn);
510 if( pOrderBy==0 ){
511 codeOffset(v, p, iContinue, nColumn);
512 }
513 }
514
515 if( checkForMultiColumnSelectError(pParse, eDest, pEList->nExpr) ){
516 return 0;
517 }
518
519 switch( eDest ){
520 /* In this mode, write each query result to the key of the temporary
521 ** table iParm.
522 */
523#ifndef SQLITE_OMIT_COMPOUND_SELECT
524 case SRT_Union: {
525 sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
526 if( aff ){
527 sqlite3VdbeChangeP3(v, -1, aff, P3_STATIC);
528 }
529 sqlite3VdbeAddOp(v, OP_IdxInsert, iParm, 0);
530 break;
531 }
532
533 /* Construct a record from the query result, but instead of
534 ** saving that record, use it as a key to delete elements from
535 ** the temporary table iParm.
536 */
537 case SRT_Except: {
538 int addr;
539 addr = sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
540 sqlite3VdbeChangeP3(v, -1, aff, P3_STATIC);
541 sqlite3VdbeAddOp(v, OP_NotFound, iParm, addr+3);
542 sqlite3VdbeAddOp(v, OP_Delete, iParm, 0);
543 break;
544 }
545#endif
546
547 /* Store the result as data using a unique key.
548 */
549 case SRT_Table:
550 case SRT_EphemTab: {
551 sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
552 if( pOrderBy ){
553 pushOntoSorter(pParse, pOrderBy, p);
554 }else{
555 sqlite3VdbeAddOp(v, OP_NewRowid, iParm, 0);
556 sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
557 sqlite3VdbeAddOp(v, OP_Insert, iParm, OPFLAG_APPEND);
558 }
559 break;
560 }
561
562#ifndef SQLITE_OMIT_SUBQUERY
563 /* If we are creating a set for an "expr IN (SELECT ...)" construct,
564 ** then there should be a single item on the stack. Write this
565 ** item into the set table with bogus data.
566 */
567 case SRT_Set: {
568 int addr1 = sqlite3VdbeCurrentAddr(v);
569 int addr2;
570
571 assert( nColumn==1 );
572 sqlite3VdbeAddOp(v, OP_NotNull, -1, addr1+3);
573 sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
574 addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
575 p->affinity = sqlite3CompareAffinity(pEList->a[0].pExpr,(iParm>>16)&0xff);
576 if( pOrderBy ){
577 /* At first glance you would think we could optimize out the
578 ** ORDER BY in this case since the order of entries in the set
579 ** does not matter. But there might be a LIMIT clause, in which
580 ** case the order does matter */
581 pushOntoSorter(pParse, pOrderBy, p);
582 }else{
583 sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &p->affinity, 1);
584 sqlite3VdbeAddOp(v, OP_IdxInsert, (iParm&0x0000FFFF), 0);
585 }
586 sqlite3VdbeJumpHere(v, addr2);
587 break;
588 }
589
590 /* If any row exist in the result set, record that fact and abort.
591 */
592 case SRT_Exists: {
593 sqlite3VdbeAddOp(v, OP_MemInt, 1, iParm);
594 sqlite3VdbeAddOp(v, OP_Pop, nColumn, 0);
595 /* The LIMIT clause will terminate the loop for us */
596 break;
597 }
598
599 /* If this is a scalar select that is part of an expression, then
600 ** store the results in the appropriate memory cell and break out
601 ** of the scan loop.
602 */
603 case SRT_Mem: {
604 assert( nColumn==1 );
605 if( pOrderBy ){
606 pushOntoSorter(pParse, pOrderBy, p);
607 }else{
608 sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1);
609 /* The LIMIT clause will jump out of the loop for us */
610 }
611 break;
612 }
613#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
614
615 /* Send the data to the callback function or to a subroutine. In the
616 ** case of a subroutine, the subroutine itself is responsible for
617 ** popping the data from the stack.
618 */
619 case SRT_Subroutine:
620 case SRT_Callback: {
621 if( pOrderBy ){
622 sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
623 pushOntoSorter(pParse, pOrderBy, p);
624 }else if( eDest==SRT_Subroutine ){
625 sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm);
626 }else{
627 sqlite3VdbeAddOp(v, OP_Callback, nColumn, 0);
628 }
629 break;
630 }
631
632#if !defined(SQLITE_OMIT_TRIGGER)
633 /* Discard the results. This is used for SELECT statements inside
634 ** the body of a TRIGGER. The purpose of such selects is to call
635 ** user-defined functions that have side effects. We do not care
636 ** about the actual results of the select.
637 */
638 default: {
639 assert( eDest==SRT_Discard );
640 sqlite3VdbeAddOp(v, OP_Pop, nColumn, 0);
641 break;
642 }
643#endif
644 }
645
646 /* Jump to the end of the loop if the LIMIT is reached.
647 */
648 if( p->iLimit>=0 && pOrderBy==0 ){
649 sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iLimit);
650 sqlite3VdbeAddOp(v, OP_IfMemZero, p->iLimit, iBreak);
651 }
652 return 0;
653}
654
655/*
656** Given an expression list, generate a KeyInfo structure that records
657** the collating sequence for each expression in that expression list.
658**
659** If the ExprList is an ORDER BY or GROUP BY clause then the resulting
660** KeyInfo structure is appropriate for initializing a virtual index to
661** implement that clause. If the ExprList is the result set of a SELECT
662** then the KeyInfo structure is appropriate for initializing a virtual
663** index to implement a DISTINCT test.
664**
665** Space to hold the KeyInfo structure is obtain from malloc. The calling
666** function is responsible for seeing that this structure is eventually
667** freed. Add the KeyInfo structure to the P3 field of an opcode using
668** P3_KEYINFO_HANDOFF is the usual way of dealing with this.
669*/
670static KeyInfo *keyInfoFromExprList(Parse *pParse, ExprList *pList){
671 sqlite3 *db = pParse->db;
672 int nExpr;
673 KeyInfo *pInfo;
674 struct ExprList_item *pItem;
675 int i;
676
677 nExpr = pList->nExpr;
678 pInfo = sqliteMalloc( sizeof(*pInfo) + nExpr*(sizeof(CollSeq*)+1) );
679 if( pInfo ){
680 pInfo->aSortOrder = (u8*)&pInfo->aColl[nExpr];
681 pInfo->nField = nExpr;
682 pInfo->enc = ENC(db);
683 for(i=0, pItem=pList->a; i<nExpr; i++, pItem++){
684 CollSeq *pColl;
685 pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
686 if( !pColl ){
687 pColl = db->pDfltColl;
688 }
689 pInfo->aColl[i] = pColl;
690 pInfo->aSortOrder[i] = pItem->sortOrder;
691 }
692 }
693 return pInfo;
694}
695
696
697/*
698** If the inner loop was generated using a non-null pOrderBy argument,
699** then the results were placed in a sorter. After the loop is terminated
700** we need to run the sorter and output the results. The following
701** routine generates the code needed to do that.
702*/
703static void generateSortTail(
704 Parse *pParse, /* Parsing context */
705 Select *p, /* The SELECT statement */
706 Vdbe *v, /* Generate code into this VDBE */
707 int nColumn, /* Number of columns of data */
708 int eDest, /* Write the sorted results here */
709 int iParm /* Optional parameter associated with eDest */
710){
711 int brk = sqlite3VdbeMakeLabel(v);
712 int cont = sqlite3VdbeMakeLabel(v);
713 int addr;
714 int iTab;
715 int pseudoTab = 0;
716 ExprList *pOrderBy = p->pOrderBy;
717
718 iTab = pOrderBy->iECursor;
719 if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
720 pseudoTab = pParse->nTab++;
721 sqlite3VdbeAddOp(v, OP_OpenPseudo, pseudoTab, 0);
722 sqlite3VdbeAddOp(v, OP_SetNumColumns, pseudoTab, nColumn);
723 }
724 addr = 1 + sqlite3VdbeAddOp(v, OP_Sort, iTab, brk);
725 codeOffset(v, p, cont, 0);
726 if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
727 sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
728 }
729 sqlite3VdbeAddOp(v, OP_Column, iTab, pOrderBy->nExpr + 1);
730 switch( eDest ){
731 case SRT_Table:
732 case SRT_EphemTab: {
733 sqlite3VdbeAddOp(v, OP_NewRowid, iParm, 0);
734 sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
735 sqlite3VdbeAddOp(v, OP_Insert, iParm, OPFLAG_APPEND);
736 break;
737 }
738#ifndef SQLITE_OMIT_SUBQUERY
739 case SRT_Set: {
740 assert( nColumn==1 );
741 sqlite3VdbeAddOp(v, OP_NotNull, -1, sqlite3VdbeCurrentAddr(v)+3);
742 sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
743 sqlite3VdbeAddOp(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+3);
744 sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &p->affinity, 1);
745 sqlite3VdbeAddOp(v, OP_IdxInsert, (iParm&0x0000FFFF), 0);
746 break;
747 }
748 case SRT_Mem: {
749 assert( nColumn==1 );
750 sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1);
751 /* The LIMIT clause will terminate the loop for us */
752 break;
753 }
754#endif
755 case SRT_Callback:
756 case SRT_Subroutine: {
757 int i;
758 sqlite3VdbeAddOp(v, OP_Insert, pseudoTab, 0);
759 for(i=0; i<nColumn; i++){
760 sqlite3VdbeAddOp(v, OP_Column, pseudoTab, i);
761 }
762 if( eDest==SRT_Callback ){
763 sqlite3VdbeAddOp(v, OP_Callback, nColumn, 0);
764 }else{
765 sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm);
766 }
767 break;
768 }
769 default: {
770 /* Do nothing */
771 break;
772 }
773 }
774
775 /* Jump to the end of the loop when the LIMIT is reached
776 */
777 if( p->iLimit>=0 ){
778 sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iLimit);
779 sqlite3VdbeAddOp(v, OP_IfMemZero, p->iLimit, brk);
780 }
781
782 /* The bottom of the loop
783 */
784 sqlite3VdbeResolveLabel(v, cont);
785 sqlite3VdbeAddOp(v, OP_Next, iTab, addr);
786 sqlite3VdbeResolveLabel(v, brk);
787 if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
788 sqlite3VdbeAddOp(v, OP_Close, pseudoTab, 0);
789 }
790
791}
792
793/*
794** Return a pointer to a string containing the 'declaration type' of the
795** expression pExpr. The string may be treated as static by the caller.
796**
797** The declaration type is the exact datatype definition extracted from the
798** original CREATE TABLE statement if the expression is a column. The
799** declaration type for a ROWID field is INTEGER. Exactly when an expression
800** is considered a column can be complex in the presence of subqueries. The
801** result-set expression in all of the following SELECT statements is
802** considered a column by this function.
803**
804** SELECT col FROM tbl;
805** SELECT (SELECT col FROM tbl;
806** SELECT (SELECT col FROM tbl);
807** SELECT abc FROM (SELECT col AS abc FROM tbl);
808**
809** The declaration type for any expression other than a column is NULL.
810*/
811static const char *columnType(
812 NameContext *pNC,
813 Expr *pExpr,
814 const char **pzOriginDb,
815 const char **pzOriginTab,
816 const char **pzOriginCol
817){
818 char const *zType = 0;
819 char const *zOriginDb = 0;
820 char const *zOriginTab = 0;
821 char const *zOriginCol = 0;
822 int j;
823 if( pExpr==0 || pNC->pSrcList==0 ) return 0;
824
825 switch( pExpr->op ){
826 case TK_AGG_COLUMN:
827 case TK_COLUMN: {
828 /* The expression is a column. Locate the table the column is being
829 ** extracted from in NameContext.pSrcList. This table may be real
830 ** database table or a subquery.
831 */
832 Table *pTab = 0; /* Table structure column is extracted from */
833 Select *pS = 0; /* Select the column is extracted from */
834 int iCol = pExpr->iColumn; /* Index of column in pTab */
835 while( pNC && !pTab ){
836 SrcList *pTabList = pNC->pSrcList;
837 for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
838 if( j<pTabList->nSrc ){
839 pTab = pTabList->a[j].pTab;
840 pS = pTabList->a[j].pSelect;
841 }else{
842 pNC = pNC->pNext;
843 }
844 }
845
846 if( pTab==0 ){
847 /* FIX ME:
848 ** This can occurs if you have something like "SELECT new.x;" inside
849 ** a trigger. In other words, if you reference the special "new"
850 ** table in the result set of a select. We do not have a good way
851 ** to find the actual table type, so call it "TEXT". This is really
852 ** something of a bug, but I do not know how to fix it.
853 **
854 ** This code does not produce the correct answer - it just prevents
855 ** a segfault. See ticket #1229.
856 */
857 zType = "TEXT";
858 break;
859 }
860
861 assert( pTab );
862 if( pS ){
863 /* The "table" is actually a sub-select or a view in the FROM clause
864 ** of the SELECT statement. Return the declaration type and origin
865 ** data for the result-set column of the sub-select.
866 */
867 if( iCol>=0 && iCol<pS->pEList->nExpr ){
868 /* If iCol is less than zero, then the expression requests the
869 ** rowid of the sub-select or view. This expression is legal (see
870 ** test case misc2.2.2) - it always evaluates to NULL.
871 */
872 NameContext sNC;
873 Expr *p = pS->pEList->a[iCol].pExpr;
874 sNC.pSrcList = pS->pSrc;
875 sNC.pNext = 0;
876 sNC.pParse = pNC->pParse;
877 zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol);
878 }
879 }else if( pTab->pSchema ){
880 /* A real table */
881 assert( !pS );
882 if( iCol<0 ) iCol = pTab->iPKey;
883 assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
884 if( iCol<0 ){
885 zType = "INTEGER";
886 zOriginCol = "rowid";
887 }else{
888 zType = pTab->aCol[iCol].zType;
889 zOriginCol = pTab->aCol[iCol].zName;
890 }
891 zOriginTab = pTab->zName;
892 if( pNC->pParse ){
893 int iDb = sqlite3SchemaToIndex(pNC->pParse->db, pTab->pSchema);
894 zOriginDb = pNC->pParse->db->aDb[iDb].zName;
895 }
896 }
897 break;
898 }
899#ifndef SQLITE_OMIT_SUBQUERY
900 case TK_SELECT: {
901 /* The expression is a sub-select. Return the declaration type and
902 ** origin info for the single column in the result set of the SELECT
903 ** statement.
904 */
905 NameContext sNC;
906 Select *pS = pExpr->pSelect;
907 Expr *p = pS->pEList->a[0].pExpr;
908 sNC.pSrcList = pS->pSrc;
909 sNC.pNext = pNC;
910 sNC.pParse = pNC->pParse;
911 zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol);
912 break;
913 }
914#endif
915 }
916
917 if( pzOriginDb ){
918 assert( pzOriginTab && pzOriginCol );
919 *pzOriginDb = zOriginDb;
920 *pzOriginTab = zOriginTab;
921 *pzOriginCol = zOriginCol;
922 }
923 return zType;
924}
925
926/*
927** Generate code that will tell the VDBE the declaration types of columns
928** in the result set.
929*/
930static void generateColumnTypes(
931 Parse *pParse, /* Parser context */
932 SrcList *pTabList, /* List of tables */
933 ExprList *pEList /* Expressions defining the result set */
934){
935 Vdbe *v = pParse->pVdbe;
936 int i;
937 NameContext sNC;
938 sNC.pSrcList = pTabList;
939 sNC.pParse = pParse;
940 for(i=0; i<pEList->nExpr; i++){
941 Expr *p = pEList->a[i].pExpr;
942 const char *zOrigDb = 0;
943 const char *zOrigTab = 0;
944 const char *zOrigCol = 0;
945 const char *zType = columnType(&sNC, p, &zOrigDb, &zOrigTab, &zOrigCol);
946
947 /* The vdbe must make it's own copy of the column-type and other
948 ** column specific strings, in case the schema is reset before this
949 ** virtual machine is deleted.
950 */
951 sqlite3VdbeSetColName(v, i, COLNAME_DECLTYPE, zType, P3_TRANSIENT);
952 sqlite3VdbeSetColName(v, i, COLNAME_DATABASE, zOrigDb, P3_TRANSIENT);
953 sqlite3VdbeSetColName(v, i, COLNAME_TABLE, zOrigTab, P3_TRANSIENT);
954 sqlite3VdbeSetColName(v, i, COLNAME_COLUMN, zOrigCol, P3_TRANSIENT);
955 }
956}
957
958/*
959** Generate code that will tell the VDBE the names of columns
960** in the result set. This information is used to provide the
961** azCol[] values in the callback.
962*/
963static void generateColumnNames(
964 Parse *pParse, /* Parser context */
965 SrcList *pTabList, /* List of tables */
966 ExprList *pEList /* Expressions defining the result set */
967){
968 Vdbe *v = pParse->pVdbe;
969 int i, j;
970 sqlite3 *db = pParse->db;
971 int fullNames, shortNames;
972
973#ifndef SQLITE_OMIT_EXPLAIN
974 /* If this is an EXPLAIN, skip this step */
975 if( pParse->explain ){
976 return;
977 }
978#endif
979
980 assert( v!=0 );
981 if( pParse->colNamesSet || v==0 || sqlite3MallocFailed() ) return;
982 pParse->colNamesSet = 1;
983 fullNames = (db->flags & SQLITE_FullColNames)!=0;
984 shortNames = (db->flags & SQLITE_ShortColNames)!=0;
985 sqlite3VdbeSetNumCols(v, pEList->nExpr);
986 for(i=0; i<pEList->nExpr; i++){
987 Expr *p;
988 p = pEList->a[i].pExpr;
989 if( p==0 ) continue;
990 if( pEList->a[i].zName ){
991 char *zName = pEList->a[i].zName;
992 sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, strlen(zName));
993 continue;
994 }
995 if( p->op==TK_COLUMN && pTabList ){
996 Table *pTab;
997 char *zCol;
998 int iCol = p->iColumn;
999 for(j=0; j<pTabList->nSrc && pTabList->a[j].iCursor!=p->iTable; j++){}
1000 assert( j<pTabList->nSrc );
1001 pTab = pTabList->a[j].pTab;
1002 if( iCol<0 ) iCol = pTab->iPKey;
1003 assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
1004 if( iCol<0 ){
1005 zCol = "rowid";
1006 }else{
1007 zCol = pTab->aCol[iCol].zName;
1008 }
1009 if( !shortNames && !fullNames && p->span.z && p->span.z[0] ){
1010 sqlite3VdbeSetColName(v, i, COLNAME_NAME, (char*)p->span.z, p->span.n);
1011 }else if( fullNames || (!shortNames && pTabList->nSrc>1) ){
1012 char *zName = 0;
1013 char *zTab;
1014
1015 zTab = pTabList->a[j].zAlias;
1016 if( fullNames || zTab==0 ) zTab = pTab->zName;
1017 sqlite3SetString(&zName, zTab, ".", zCol, (char*)0);
1018 sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, P3_DYNAMIC);
1019 }else{
1020 sqlite3VdbeSetColName(v, i, COLNAME_NAME, zCol, strlen(zCol));
1021 }
1022 }else if( p->span.z && p->span.z[0] ){
1023 sqlite3VdbeSetColName(v, i, COLNAME_NAME, (char*)p->span.z, p->span.n);
1024 /* sqlite3VdbeCompressSpace(v, addr); */
1025 }else{
1026 char zName[30];
1027 assert( p->op!=TK_COLUMN || pTabList==0 );
1028 sqlite3_snprintf(sizeof(zName), zName, "column%d", i+1);
1029 sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, 0);
1030 }
1031 }
1032 generateColumnTypes(pParse, pTabList, pEList);
1033}
1034
1035#ifndef SQLITE_OMIT_COMPOUND_SELECT
1036/*
1037** Name of the connection operator, used for error messages.
1038*/
1039static const char *selectOpName(int id){
1040 char *z;
1041 switch( id ){
1042 case TK_ALL: z = "UNION ALL"; break;
1043 case TK_INTERSECT: z = "INTERSECT"; break;
1044 case TK_EXCEPT: z = "EXCEPT"; break;
1045 default: z = "UNION"; break;
1046 }
1047 return z;
1048}
1049#endif /* SQLITE_OMIT_COMPOUND_SELECT */
1050
1051/*
1052** Forward declaration
1053*/
1054static int prepSelectStmt(Parse*, Select*);
1055
1056/*
1057** Given a SELECT statement, generate a Table structure that describes
1058** the result set of that SELECT.
1059*/
1060Table *sqlite3ResultSetOfSelect(Parse *pParse, char *zTabName, Select *pSelect){
1061 Table *pTab;
1062 int i, j;
1063 ExprList *pEList;
1064 Column *aCol, *pCol;
1065
1066 while( pSelect->pPrior ) pSelect = pSelect->pPrior;
1067 if( prepSelectStmt(pParse, pSelect) ){
1068 return 0;
1069 }
1070 if( sqlite3SelectResolve(pParse, pSelect, 0) ){
1071 return 0;
1072 }
1073 pTab = sqliteMalloc( sizeof(Table) );
1074 if( pTab==0 ){
1075 return 0;
1076 }
1077 pTab->nRef = 1;
1078 pTab->zName = zTabName ? sqliteStrDup(zTabName) : 0;
1079 pEList = pSelect->pEList;
1080 pTab->nCol = pEList->nExpr;
1081 assert( pTab->nCol>0 );
1082 pTab->aCol = aCol = sqliteMalloc( sizeof(pTab->aCol[0])*pTab->nCol );
1083 for(i=0, pCol=aCol; i<pTab->nCol; i++, pCol++){
1084 Expr *p, *pR;
1085 char *zType;
1086 char *zName;
1087 int nName;
1088 CollSeq *pColl;
1089 int cnt;
1090 NameContext sNC;
1091
1092 /* Get an appropriate name for the column
1093 */
1094 p = pEList->a[i].pExpr;
1095 assert( p->pRight==0 || p->pRight->token.z==0 || p->pRight->token.z[0]!=0 );
1096 if( (zName = pEList->a[i].zName)!=0 ){
1097 /* If the column contains an "AS <name>" phrase, use <name> as the name */
1098 zName = sqliteStrDup(zName);
1099 }else if( p->op==TK_DOT
1100 && (pR=p->pRight)!=0 && pR->token.z && pR->token.z[0] ){
1101 /* For columns of the from A.B use B as the name */
1102 zName = sqlite3MPrintf("%T", &pR->token);
1103 }else if( p->span.z && p->span.z[0] ){
1104 /* Use the original text of the column expression as its name */
1105 zName = sqlite3MPrintf("%T", &p->span);
1106 }else{
1107 /* If all else fails, make up a name */
1108 zName = sqlite3MPrintf("column%d", i+1);
1109 }
1110 sqlite3Dequote(zName);
1111 if( sqlite3MallocFailed() ){
1112 sqliteFree(zName);
1113 sqlite3DeleteTable(pTab);
1114 return 0;
1115 }
1116
1117 /* Make sure the column name is unique. If the name is not unique,
1118 ** append a integer to the name so that it becomes unique.
1119 */
1120 nName = strlen(zName);
1121 for(j=cnt=0; j<i; j++){
1122 if( sqlite3StrICmp(aCol[j].zName, zName)==0 ){
1123 zName[nName] = 0;
1124 zName = sqlite3MPrintf("%z:%d", zName, ++cnt);
1125 j = -1;
1126 if( zName==0 ) break;
1127 }
1128 }
1129 pCol->zName = zName;
1130
1131 /* Get the typename, type affinity, and collating sequence for the
1132 ** column.
1133 */
1134 memset(&sNC, 0, sizeof(sNC));
1135 sNC.pSrcList = pSelect->pSrc;
1136 zType = sqliteStrDup(columnType(&sNC, p, 0, 0, 0));
1137 pCol->zType = zType;
1138 pCol->affinity = sqlite3ExprAffinity(p);
1139 pColl = sqlite3ExprCollSeq(pParse, p);
1140 if( pColl ){
1141 pCol->zColl = sqliteStrDup(pColl->zName);
1142 }
1143 }
1144 pTab->iPKey = -1;
1145 return pTab;
1146}
1147
1148/*
1149** Prepare a SELECT statement for processing by doing the following
1150** things:
1151**
1152** (1) Make sure VDBE cursor numbers have been assigned to every
1153** element of the FROM clause.
1154**
1155** (2) Fill in the pTabList->a[].pTab fields in the SrcList that
1156** defines FROM clause. When views appear in the FROM clause,
1157** fill pTabList->a[].pSelect with a copy of the SELECT statement
1158** that implements the view. A copy is made of the view's SELECT
1159** statement so that we can freely modify or delete that statement
1160** without worrying about messing up the presistent representation
1161** of the view.
1162**
1163** (3) Add terms to the WHERE clause to accomodate the NATURAL keyword
1164** on joins and the ON and USING clause of joins.
1165**
1166** (4) Scan the list of columns in the result set (pEList) looking
1167** for instances of the "*" operator or the TABLE.* operator.
1168** If found, expand each "*" to be every column in every table
1169** and TABLE.* to be every column in TABLE.
1170**
1171** Return 0 on success. If there are problems, leave an error message
1172** in pParse and return non-zero.
1173*/
1174static int prepSelectStmt(Parse *pParse, Select *p){
1175 int i, j, k, rc;
1176 SrcList *pTabList;
1177 ExprList *pEList;
1178 struct SrcList_item *pFrom;
1179
1180 if( p==0 || p->pSrc==0 || sqlite3MallocFailed() ){
1181 return 1;
1182 }
1183 pTabList = p->pSrc;
1184 pEList = p->pEList;
1185
1186 /* Make sure cursor numbers have been assigned to all entries in
1187 ** the FROM clause of the SELECT statement.
1188 */
1189 sqlite3SrcListAssignCursors(pParse, p->pSrc);
1190
1191 /* Look up every table named in the FROM clause of the select. If
1192 ** an entry of the FROM clause is a subquery instead of a table or view,
1193 ** then create a transient table structure to describe the subquery.
1194 */
1195 for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
1196 Table *pTab;
1197 if( pFrom->pTab!=0 ){
1198 /* This statement has already been prepared. There is no need
1199 ** to go further. */
1200 assert( i==0 );
1201 return 0;
1202 }
1203 if( pFrom->zName==0 ){
1204#ifndef SQLITE_OMIT_SUBQUERY
1205 /* A sub-query in the FROM clause of a SELECT */
1206 assert( pFrom->pSelect!=0 );
1207 if( pFrom->zAlias==0 ){
1208 pFrom->zAlias =
1209 sqlite3MPrintf("sqlite_subquery_%p_", (void*)pFrom->pSelect);
1210 }
1211 assert( pFrom->pTab==0 );
1212 pFrom->pTab = pTab =
1213 sqlite3ResultSetOfSelect(pParse, pFrom->zAlias, pFrom->pSelect);
1214 if( pTab==0 ){
1215 return 1;
1216 }
1217 /* The isEphem flag indicates that the Table structure has been
1218 ** dynamically allocated and may be freed at any time. In other words,
1219 ** pTab is not pointing to a persistent table structure that defines
1220 ** part of the schema. */
1221 pTab->isEphem = 1;
1222#endif
1223 }else{
1224 /* An ordinary table or view name in the FROM clause */
1225 assert( pFrom->pTab==0 );
1226 pFrom->pTab = pTab =
1227 sqlite3LocateTable(pParse,pFrom->zName,pFrom->zDatabase);
1228 if( pTab==0 ){
1229 return 1;
1230 }
1231 pTab->nRef++;
1232#if !defined(SQLITE_OMIT_VIEW) || !defined (SQLITE_OMIT_VIRTUALTABLE)
1233 if( pTab->pSelect || IsVirtual(pTab) ){
1234 /* We reach here if the named table is a really a view */
1235 if( sqlite3ViewGetColumnNames(pParse, pTab) ){
1236 return 1;
1237 }
1238 /* If pFrom->pSelect!=0 it means we are dealing with a
1239 ** view within a view. The SELECT structure has already been
1240 ** copied by the outer view so we can skip the copy step here
1241 ** in the inner view.
1242 */
1243 if( pFrom->pSelect==0 ){
1244 pFrom->pSelect = sqlite3SelectDup(pTab->pSelect);
1245 }
1246 }
1247#endif
1248 }
1249 }
1250
1251 /* Process NATURAL keywords, and ON and USING clauses of joins.
1252 */
1253 if( sqliteProcessJoin(pParse, p) ) return 1;
1254
1255 /* For every "*" that occurs in the column list, insert the names of
1256 ** all columns in all tables. And for every TABLE.* insert the names
1257 ** of all columns in TABLE. The parser inserted a special expression
1258 ** with the TK_ALL operator for each "*" that it found in the column list.
1259 ** The following code just has to locate the TK_ALL expressions and expand
1260 ** each one to the list of all columns in all tables.
1261 **
1262 ** The first loop just checks to see if there are any "*" operators
1263 ** that need expanding.
1264 */
1265 for(k=0; k<pEList->nExpr; k++){
1266 Expr *pE = pEList->a[k].pExpr;
1267 if( pE->op==TK_ALL ) break;
1268 if( pE->op==TK_DOT && pE->pRight && pE->pRight->op==TK_ALL
1269 && pE->pLeft && pE->pLeft->op==TK_ID ) break;
1270 }
1271 rc = 0;
1272 if( k<pEList->nExpr ){
1273 /*
1274 ** If we get here it means the result set contains one or more "*"
1275 ** operators that need to be expanded. Loop through each expression
1276 ** in the result set and expand them one by one.
1277 */
1278 struct ExprList_item *a = pEList->a;
1279 ExprList *pNew = 0;
1280 int flags = pParse->db->flags;
1281 int longNames = (flags & SQLITE_FullColNames)!=0 &&
1282 (flags & SQLITE_ShortColNames)==0;
1283
1284 for(k=0; k<pEList->nExpr; k++){
1285 Expr *pE = a[k].pExpr;
1286 if( pE->op!=TK_ALL &&
1287 (pE->op!=TK_DOT || pE->pRight==0 || pE->pRight->op!=TK_ALL) ){
1288 /* This particular expression does not need to be expanded.
1289 */
1290 pNew = sqlite3ExprListAppend(pNew, a[k].pExpr, 0);
1291 if( pNew ){
1292 pNew->a[pNew->nExpr-1].zName = a[k].zName;
1293 }else{
1294 rc = 1;
1295 }
1296 a[k].pExpr = 0;
1297 a[k].zName = 0;
1298 }else{
1299 /* This expression is a "*" or a "TABLE.*" and needs to be
1300 ** expanded. */
1301 int tableSeen = 0; /* Set to 1 when TABLE matches */
1302 char *zTName; /* text of name of TABLE */
1303 if( pE->op==TK_DOT && pE->pLeft ){
1304 zTName = sqlite3NameFromToken(&pE->pLeft->token);
1305 }else{
1306 zTName = 0;
1307 }
1308 for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
1309 Table *pTab = pFrom->pTab;
1310 char *zTabName = pFrom->zAlias;
1311 if( zTabName==0 || zTabName[0]==0 ){
1312 zTabName = pTab->zName;
1313 }
1314 if( zTName && (zTabName==0 || zTabName[0]==0 ||
1315 sqlite3StrICmp(zTName, zTabName)!=0) ){
1316 continue;
1317 }
1318 tableSeen = 1;
1319 for(j=0; j<pTab->nCol; j++){
1320 Expr *pExpr, *pRight;
1321 char *zName = pTab->aCol[j].zName;
1322
1323 if( i>0 ){
1324 struct SrcList_item *pLeft = &pTabList->a[i-1];
1325 if( (pLeft[1].jointype & JT_NATURAL)!=0 &&
1326 columnIndex(pLeft->pTab, zName)>=0 ){
1327 /* In a NATURAL join, omit the join columns from the
1328 ** table on the right */
1329 continue;
1330 }
1331 if( sqlite3IdListIndex(pLeft[1].pUsing, zName)>=0 ){
1332 /* In a join with a USING clause, omit columns in the
1333 ** using clause from the table on the right. */
1334 continue;
1335 }
1336 }
1337 pRight = sqlite3Expr(TK_ID, 0, 0, 0);
1338 if( pRight==0 ) break;
1339 setToken(&pRight->token, zName);
1340 if( zTabName && (longNames || pTabList->nSrc>1) ){
1341 Expr *pLeft = sqlite3Expr(TK_ID, 0, 0, 0);
1342 pExpr = sqlite3Expr(TK_DOT, pLeft, pRight, 0);
1343 if( pExpr==0 ) break;
1344 setToken(&pLeft->token, zTabName);
1345 setToken(&pExpr->span, sqlite3MPrintf("%s.%s", zTabName, zName));
1346 pExpr->span.dyn = 1;
1347 pExpr->token.z = 0;
1348 pExpr->token.n = 0;
1349 pExpr->token.dyn = 0;
1350 }else{
1351 pExpr = pRight;
1352 pExpr->span = pExpr->token;
1353 }
1354 if( longNames ){
1355 pNew = sqlite3ExprListAppend(pNew, pExpr, &pExpr->span);
1356 }else{
1357 pNew = sqlite3ExprListAppend(pNew, pExpr, &pRight->token);
1358 }
1359 }
1360 }
1361 if( !tableSeen ){
1362 if( zTName ){
1363 sqlite3ErrorMsg(pParse, "no such table: %s", zTName);
1364 }else{
1365 sqlite3ErrorMsg(pParse, "no tables specified");
1366 }
1367 rc = 1;
1368 }
1369 sqliteFree(zTName);
1370 }
1371 }
1372 sqlite3ExprListDelete(pEList);
1373 p->pEList = pNew;
1374 }
1375 if( p->pEList && p->pEList->nExpr>SQLITE_MAX_COLUMN ){
1376 sqlite3ErrorMsg(pParse, "too many columns in result set");
1377 rc = SQLITE_ERROR;
1378 }
1379 return rc;
1380}
1381
1382#ifndef SQLITE_OMIT_COMPOUND_SELECT
1383/*
1384** This routine associates entries in an ORDER BY expression list with
1385** columns in a result. For each ORDER BY expression, the opcode of
1386** the top-level node is changed to TK_COLUMN and the iColumn value of
1387** the top-level node is filled in with column number and the iTable
1388** value of the top-level node is filled with iTable parameter.
1389**
1390** If there are prior SELECT clauses, they are processed first. A match
1391** in an earlier SELECT takes precedence over a later SELECT.
1392**
1393** Any entry that does not match is flagged as an error. The number
1394** of errors is returned.
1395*/
1396static int matchOrderbyToColumn(
1397 Parse *pParse, /* A place to leave error messages */
1398 Select *pSelect, /* Match to result columns of this SELECT */
1399 ExprList *pOrderBy, /* The ORDER BY values to match against columns */
1400 int iTable, /* Insert this value in iTable */
1401 int mustComplete /* If TRUE all ORDER BYs must match */
1402){
1403 int nErr = 0;
1404 int i, j;
1405 ExprList *pEList;
1406
1407 if( pSelect==0 || pOrderBy==0 ) return 1;
1408 if( mustComplete ){
1409 for(i=0; i<pOrderBy->nExpr; i++){ pOrderBy->a[i].done = 0; }
1410 }
1411 if( prepSelectStmt(pParse, pSelect) ){
1412 return 1;
1413 }
1414 if( pSelect->pPrior ){
1415 if( matchOrderbyToColumn(pParse, pSelect->pPrior, pOrderBy, iTable, 0) ){
1416 return 1;
1417 }
1418 }
1419 pEList = pSelect->pEList;
1420 for(i=0; i<pOrderBy->nExpr; i++){
1421 struct ExprList_item *pItem;
1422 Expr *pE = pOrderBy->a[i].pExpr;
1423 int iCol = -1;
1424 char *zLabel;
1425
1426 if( pOrderBy->a[i].done ) continue;
1427 if( sqlite3ExprIsInteger(pE, &iCol) ){
1428 if( iCol<=0 || iCol>pEList->nExpr ){
1429 sqlite3ErrorMsg(pParse,
1430 "ORDER BY position %d should be between 1 and %d",
1431 iCol, pEList->nExpr);
1432 nErr++;
1433 break;
1434 }
1435 if( !mustComplete ) continue;
1436 iCol--;
1437 }
1438 if( iCol<0 && (zLabel = sqlite3NameFromToken(&pE->token))!=0 ){
1439 for(j=0, pItem=pEList->a; j<pEList->nExpr; j++, pItem++){
1440 char *zName;
1441 int isMatch;
1442 if( pItem->zName ){
1443 zName = sqlite3StrDup(pItem->zName);
1444 }else{
1445 zName = sqlite3NameFromToken(&pItem->pExpr->token);
1446 }
1447 isMatch = zName && sqlite3StrICmp(zName, zLabel)==0;
1448 sqliteFree(zName);
1449 if( isMatch ){
1450 iCol = j;
1451 break;
1452 }
1453 }
1454 sqliteFree(zLabel);
1455 }
1456 if( iCol>=0 ){
1457 pE->op = TK_COLUMN;
1458 pE->iColumn = iCol;
1459 pE->iTable = iTable;
1460 pE->iAgg = -1;
1461 pOrderBy->a[i].done = 1;
1462 }else if( mustComplete ){
1463 sqlite3ErrorMsg(pParse,
1464 "ORDER BY term number %d does not match any result column", i+1);
1465 nErr++;
1466 break;
1467 }
1468 }
1469 return nErr;
1470}
1471#endif /* #ifndef SQLITE_OMIT_COMPOUND_SELECT */
1472
1473/*
1474** Get a VDBE for the given parser context. Create a new one if necessary.
1475** If an error occurs, return NULL and leave a message in pParse.
1476*/
1477Vdbe *sqlite3GetVdbe(Parse *pParse){
1478 Vdbe *v = pParse->pVdbe;
1479 if( v==0 ){
1480 v = pParse->pVdbe = sqlite3VdbeCreate(pParse->db);
1481 }
1482 return v;
1483}
1484
1485
1486/*
1487** Compute the iLimit and iOffset fields of the SELECT based on the
1488** pLimit and pOffset expressions. pLimit and pOffset hold the expressions
1489** that appear in the original SQL statement after the LIMIT and OFFSET
1490** keywords. Or NULL if those keywords are omitted. iLimit and iOffset
1491** are the integer memory register numbers for counters used to compute
1492** the limit and offset. If there is no limit and/or offset, then
1493** iLimit and iOffset are negative.
1494**
1495** This routine changes the values of iLimit and iOffset only if
1496** a limit or offset is defined by pLimit and pOffset. iLimit and
1497** iOffset should have been preset to appropriate default values
1498** (usually but not always -1) prior to calling this routine.
1499** Only if pLimit!=0 or pOffset!=0 do the limit registers get
1500** redefined. The UNION ALL operator uses this property to force
1501** the reuse of the same limit and offset registers across multiple
1502** SELECT statements.
1503*/
1504static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
1505 Vdbe *v = 0;
1506 int iLimit = 0;
1507 int iOffset;
1508 int addr1, addr2;
1509
1510 /*
1511 ** "LIMIT -1" always shows all rows. There is some
1512 ** contraversy about what the correct behavior should be.
1513 ** The current implementation interprets "LIMIT 0" to mean
1514 ** no rows.
1515 */
1516 if( p->pLimit ){
1517 p->iLimit = iLimit = pParse->nMem;
1518 pParse->nMem += 2;
1519 v = sqlite3GetVdbe(pParse);
1520 if( v==0 ) return;
1521 sqlite3ExprCode(pParse, p->pLimit);
1522 sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
1523 sqlite3VdbeAddOp(v, OP_MemStore, iLimit, 1);
1524 VdbeComment((v, "# LIMIT counter"));
1525 sqlite3VdbeAddOp(v, OP_IfMemZero, iLimit, iBreak);
1526 sqlite3VdbeAddOp(v, OP_MemLoad, iLimit, 0);
1527 }
1528 if( p->pOffset ){
1529 p->iOffset = iOffset = pParse->nMem++;
1530 v = sqlite3GetVdbe(pParse);
1531 if( v==0 ) return;
1532 sqlite3ExprCode(pParse, p->pOffset);
1533 sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
1534 sqlite3VdbeAddOp(v, OP_MemStore, iOffset, p->pLimit==0);
1535 VdbeComment((v, "# OFFSET counter"));
1536 addr1 = sqlite3VdbeAddOp(v, OP_IfMemPos, iOffset, 0);
1537 sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
1538 sqlite3VdbeAddOp(v, OP_Integer, 0, 0);
1539 sqlite3VdbeJumpHere(v, addr1);
1540 if( p->pLimit ){
1541 sqlite3VdbeAddOp(v, OP_Add, 0, 0);
1542 }
1543 }
1544 if( p->pLimit ){
1545 addr1 = sqlite3VdbeAddOp(v, OP_IfMemPos, iLimit, 0);
1546 sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
1547 sqlite3VdbeAddOp(v, OP_MemInt, -1, iLimit+1);
1548 addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
1549 sqlite3VdbeJumpHere(v, addr1);
1550 sqlite3VdbeAddOp(v, OP_MemStore, iLimit+1, 1);
1551 VdbeComment((v, "# LIMIT+OFFSET"));
1552 sqlite3VdbeJumpHere(v, addr2);
1553 }
1554}
1555
1556/*
1557** Allocate a virtual index to use for sorting.
1558*/
1559static void createSortingIndex(Parse *pParse, Select *p, ExprList *pOrderBy){
1560 if( pOrderBy ){
1561 int addr;
1562 assert( pOrderBy->iECursor==0 );
1563 pOrderBy->iECursor = pParse->nTab++;
1564 addr = sqlite3VdbeAddOp(pParse->pVdbe, OP_OpenEphemeral,
1565 pOrderBy->iECursor, pOrderBy->nExpr+1);
1566 assert( p->addrOpenEphm[2] == -1 );
1567 p->addrOpenEphm[2] = addr;
1568 }
1569}
1570
1571#ifndef SQLITE_OMIT_COMPOUND_SELECT
1572/*
1573** Return the appropriate collating sequence for the iCol-th column of
1574** the result set for the compound-select statement "p". Return NULL if
1575** the column has no default collating sequence.
1576**
1577** The collating sequence for the compound select is taken from the
1578** left-most term of the select that has a collating sequence.
1579*/
1580static CollSeq *multiSelectCollSeq(Parse *pParse, Select *p, int iCol){
1581 CollSeq *pRet;
1582 if( p->pPrior ){
1583 pRet = multiSelectCollSeq(pParse, p->pPrior, iCol);
1584 }else{
1585 pRet = 0;
1586 }
1587 if( pRet==0 ){
1588 pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr);
1589 }
1590 return pRet;
1591}
1592#endif /* SQLITE_OMIT_COMPOUND_SELECT */
1593
1594#ifndef SQLITE_OMIT_COMPOUND_SELECT
1595/*
1596** This routine is called to process a query that is really the union
1597** or intersection of two or more separate queries.
1598**
1599** "p" points to the right-most of the two queries. the query on the
1600** left is p->pPrior. The left query could also be a compound query
1601** in which case this routine will be called recursively.
1602**
1603** The results of the total query are to be written into a destination
1604** of type eDest with parameter iParm.
1605**
1606** Example 1: Consider a three-way compound SQL statement.
1607**
1608** SELECT a FROM t1 UNION SELECT b FROM t2 UNION SELECT c FROM t3
1609**
1610** This statement is parsed up as follows:
1611**
1612** SELECT c FROM t3
1613** |
1614** `-----> SELECT b FROM t2
1615** |
1616** `------> SELECT a FROM t1
1617**
1618** The arrows in the diagram above represent the Select.pPrior pointer.
1619** So if this routine is called with p equal to the t3 query, then
1620** pPrior will be the t2 query. p->op will be TK_UNION in this case.
1621**
1622** Notice that because of the way SQLite parses compound SELECTs, the
1623** individual selects always group from left to right.
1624*/
1625static int multiSelect(
1626 Parse *pParse, /* Parsing context */
1627 Select *p, /* The right-most of SELECTs to be coded */
1628 int eDest, /* \___ Store query results as specified */
1629 int iParm, /* / by these two parameters. */
1630 char *aff /* If eDest is SRT_Union, the affinity string */
1631){
1632 int rc = SQLITE_OK; /* Success code from a subroutine */
1633 Select *pPrior; /* Another SELECT immediately to our left */
1634 Vdbe *v; /* Generate code to this VDBE */
1635 int nCol; /* Number of columns in the result set */
1636 ExprList *pOrderBy; /* The ORDER BY clause on p */
1637 int aSetP2[2]; /* Set P2 value of these op to number of columns */
1638 int nSetP2 = 0; /* Number of slots in aSetP2[] used */
1639
1640 /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs. Only
1641 ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
1642 */
1643 if( p==0 || p->pPrior==0 ){
1644 rc = 1;
1645 goto multi_select_end;
1646 }
1647 pPrior = p->pPrior;
1648 assert( pPrior->pRightmost!=pPrior );
1649 assert( pPrior->pRightmost==p->pRightmost );
1650 if( pPrior->pOrderBy ){
1651 sqlite3ErrorMsg(pParse,"ORDER BY clause should come after %s not before",
1652 selectOpName(p->op));
1653 rc = 1;
1654 goto multi_select_end;
1655 }
1656 if( pPrior->pLimit ){
1657 sqlite3ErrorMsg(pParse,"LIMIT clause should come after %s not before",
1658 selectOpName(p->op));
1659 rc = 1;
1660 goto multi_select_end;
1661 }
1662
1663 /* Make sure we have a valid query engine. If not, create a new one.
1664 */
1665 v = sqlite3GetVdbe(pParse);
1666 if( v==0 ){
1667 rc = 1;
1668 goto multi_select_end;
1669 }
1670
1671 /* Create the destination temporary table if necessary
1672 */
1673 if( eDest==SRT_EphemTab ){
1674 assert( p->pEList );
1675 assert( nSetP2<sizeof(aSetP2)/sizeof(aSetP2[0]) );
1676 aSetP2[nSetP2++] = sqlite3VdbeAddOp(v, OP_OpenEphemeral, iParm, 0);
1677 eDest = SRT_Table;
1678 }
1679
1680 /* Generate code for the left and right SELECT statements.
1681 */
1682 pOrderBy = p->pOrderBy;
1683 switch( p->op ){
1684 case TK_ALL: {
1685 if( pOrderBy==0 ){
1686 int addr = 0;
1687 assert( !pPrior->pLimit );
1688 pPrior->pLimit = p->pLimit;
1689 pPrior->pOffset = p->pOffset;
1690 rc = sqlite3Select(pParse, pPrior, eDest, iParm, 0, 0, 0, aff);
1691 p->pLimit = 0;
1692 p->pOffset = 0;
1693 if( rc ){
1694 goto multi_select_end;
1695 }
1696 p->pPrior = 0;
1697 p->iLimit = pPrior->iLimit;
1698 p->iOffset = pPrior->iOffset;
1699 if( p->iLimit>=0 ){
1700 addr = sqlite3VdbeAddOp(v, OP_IfMemZero, p->iLimit, 0);
1701 VdbeComment((v, "# Jump ahead if LIMIT reached"));
1702 }
1703 rc = sqlite3Select(pParse, p, eDest, iParm, 0, 0, 0, aff);
1704 p->pPrior = pPrior;
1705 if( rc ){
1706 goto multi_select_end;
1707 }
1708 if( addr ){
1709 sqlite3VdbeJumpHere(v, addr);
1710 }
1711 break;
1712 }
1713 /* For UNION ALL ... ORDER BY fall through to the next case */
1714 }
1715 case TK_EXCEPT:
1716 case TK_UNION: {
1717 int unionTab; /* Cursor number of the temporary table holding result */
1718 int op = 0; /* One of the SRT_ operations to apply to self */
1719 int priorOp; /* The SRT_ operation to apply to prior selects */
1720 Expr *pLimit, *pOffset; /* Saved values of p->nLimit and p->nOffset */
1721 int addr;
1722
1723 priorOp = p->op==TK_ALL ? SRT_Table : SRT_Union;
1724 if( eDest==priorOp && pOrderBy==0 && !p->pLimit && !p->pOffset ){
1725 /* We can reuse a temporary table generated by a SELECT to our
1726 ** right.
1727 */
1728 unionTab = iParm;
1729 }else{
1730 /* We will need to create our own temporary table to hold the
1731 ** intermediate results.
1732 */
1733 unionTab = pParse->nTab++;
1734 if( pOrderBy && matchOrderbyToColumn(pParse, p, pOrderBy, unionTab,1) ){
1735 rc = 1;
1736 goto multi_select_end;
1737 }
1738 addr = sqlite3VdbeAddOp(v, OP_OpenEphemeral, unionTab, 0);
1739 if( priorOp==SRT_Table ){
1740 assert( nSetP2<sizeof(aSetP2)/sizeof(aSetP2[0]) );
1741 aSetP2[nSetP2++] = addr;
1742 }else{
1743 assert( p->addrOpenEphm[0] == -1 );
1744 p->addrOpenEphm[0] = addr;
1745 p->pRightmost->usesEphm = 1;
1746 }
1747 createSortingIndex(pParse, p, pOrderBy);
1748 assert( p->pEList );
1749 }
1750
1751 /* Code the SELECT statements to our left
1752 */
1753 assert( !pPrior->pOrderBy );
1754 rc = sqlite3Select(pParse, pPrior, priorOp, unionTab, 0, 0, 0, aff);
1755 if( rc ){
1756 goto multi_select_end;
1757 }
1758
1759 /* Code the current SELECT statement
1760 */
1761 switch( p->op ){
1762 case TK_EXCEPT: op = SRT_Except; break;
1763 case TK_UNION: op = SRT_Union; break;
1764 case TK_ALL: op = SRT_Table; break;
1765 }
1766 p->pPrior = 0;
1767 p->pOrderBy = 0;
1768 p->disallowOrderBy = pOrderBy!=0;
1769 pLimit = p->pLimit;
1770 p->pLimit = 0;
1771 pOffset = p->pOffset;
1772 p->pOffset = 0;
1773 rc = sqlite3Select(pParse, p, op, unionTab, 0, 0, 0, aff);
1774 /* Query flattening in sqlite3Select() might refill p->pOrderBy.
1775 ** Be sure to delete p->pOrderBy, therefore, to avoid a memory leak. */
1776 sqlite3ExprListDelete(p->pOrderBy);
1777 p->pPrior = pPrior;
1778 p->pOrderBy = pOrderBy;
1779 sqlite3ExprDelete(p->pLimit);
1780 p->pLimit = pLimit;
1781 p->pOffset = pOffset;
1782 p->iLimit = -1;
1783 p->iOffset = -1;
1784 if( rc ){
1785 goto multi_select_end;
1786 }
1787
1788
1789 /* Convert the data in the temporary table into whatever form
1790 ** it is that we currently need.
1791 */
1792 if( eDest!=priorOp || unionTab!=iParm ){
1793 int iCont, iBreak, iStart;
1794 assert( p->pEList );
1795 if( eDest==SRT_Callback ){
1796 Select *pFirst = p;
1797 while( pFirst->pPrior ) pFirst = pFirst->pPrior;
1798 generateColumnNames(pParse, 0, pFirst->pEList);
1799 }
1800 iBreak = sqlite3VdbeMakeLabel(v);
1801 iCont = sqlite3VdbeMakeLabel(v);
1802 computeLimitRegisters(pParse, p, iBreak);
1803 sqlite3VdbeAddOp(v, OP_Rewind, unionTab, iBreak);
1804 iStart = sqlite3VdbeCurrentAddr(v);
1805 rc = selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr,
1806 pOrderBy, -1, eDest, iParm,
1807 iCont, iBreak, 0);
1808 if( rc ){
1809 rc = 1;
1810 goto multi_select_end;
1811 }
1812 sqlite3VdbeResolveLabel(v, iCont);
1813 sqlite3VdbeAddOp(v, OP_Next, unionTab, iStart);
1814 sqlite3VdbeResolveLabel(v, iBreak);
1815 sqlite3VdbeAddOp(v, OP_Close, unionTab, 0);
1816 }
1817 break;
1818 }
1819 case TK_INTERSECT: {
1820 int tab1, tab2;
1821 int iCont, iBreak, iStart;
1822 Expr *pLimit, *pOffset;
1823 int addr;
1824
1825 /* INTERSECT is different from the others since it requires
1826 ** two temporary tables. Hence it has its own case. Begin
1827 ** by allocating the tables we will need.
1828 */
1829 tab1 = pParse->nTab++;
1830 tab2 = pParse->nTab++;
1831 if( pOrderBy && matchOrderbyToColumn(pParse,p,pOrderBy,tab1,1) ){
1832 rc = 1;
1833 goto multi_select_end;
1834 }
1835 createSortingIndex(pParse, p, pOrderBy);
1836
1837 addr = sqlite3VdbeAddOp(v, OP_OpenEphemeral, tab1, 0);
1838 assert( p->addrOpenEphm[0] == -1 );
1839 p->addrOpenEphm[0] = addr;
1840 p->pRightmost->usesEphm = 1;
1841 assert( p->pEList );
1842
1843 /* Code the SELECTs to our left into temporary table "tab1".
1844 */
1845 rc = sqlite3Select(pParse, pPrior, SRT_Union, tab1, 0, 0, 0, aff);
1846 if( rc ){
1847 goto multi_select_end;
1848 }
1849
1850 /* Code the current SELECT into temporary table "tab2"
1851 */
1852 addr = sqlite3VdbeAddOp(v, OP_OpenEphemeral, tab2, 0);
1853 assert( p->addrOpenEphm[1] == -1 );
1854 p->addrOpenEphm[1] = addr;
1855 p->pPrior = 0;
1856 pLimit = p->pLimit;
1857 p->pLimit = 0;
1858 pOffset = p->pOffset;
1859 p->pOffset = 0;
1860 rc = sqlite3Select(pParse, p, SRT_Union, tab2, 0, 0, 0, aff);
1861 p->pPrior = pPrior;
1862 sqlite3ExprDelete(p->pLimit);
1863 p->pLimit = pLimit;
1864 p->pOffset = pOffset;
1865 if( rc ){
1866 goto multi_select_end;
1867 }
1868
1869 /* Generate code to take the intersection of the two temporary
1870 ** tables.
1871 */
1872 assert( p->pEList );
1873 if( eDest==SRT_Callback ){
1874 Select *pFirst = p;
1875 while( pFirst->pPrior ) pFirst = pFirst->pPrior;
1876 generateColumnNames(pParse, 0, pFirst->pEList);
1877 }
1878 iBreak = sqlite3VdbeMakeLabel(v);
1879 iCont = sqlite3VdbeMakeLabel(v);
1880 computeLimitRegisters(pParse, p, iBreak);
1881 sqlite3VdbeAddOp(v, OP_Rewind, tab1, iBreak);
1882 iStart = sqlite3VdbeAddOp(v, OP_RowKey, tab1, 0);
1883 sqlite3VdbeAddOp(v, OP_NotFound, tab2, iCont);
1884 rc = selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
1885 pOrderBy, -1, eDest, iParm,
1886 iCont, iBreak, 0);
1887 if( rc ){
1888 rc = 1;
1889 goto multi_select_end;
1890 }
1891 sqlite3VdbeResolveLabel(v, iCont);
1892 sqlite3VdbeAddOp(v, OP_Next, tab1, iStart);
1893 sqlite3VdbeResolveLabel(v, iBreak);
1894 sqlite3VdbeAddOp(v, OP_Close, tab2, 0);
1895 sqlite3VdbeAddOp(v, OP_Close, tab1, 0);
1896 break;
1897 }
1898 }
1899
1900 /* Make sure all SELECTs in the statement have the same number of elements
1901 ** in their result sets.
1902 */
1903 assert( p->pEList && pPrior->pEList );
1904 if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
1905 sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
1906 " do not have the same number of result columns", selectOpName(p->op));
1907 rc = 1;
1908 goto multi_select_end;
1909 }
1910
1911 /* Set the number of columns in temporary tables
1912 */
1913 nCol = p->pEList->nExpr;
1914 while( nSetP2 ){
1915 sqlite3VdbeChangeP2(v, aSetP2[--nSetP2], nCol);
1916 }
1917
1918 /* Compute collating sequences used by either the ORDER BY clause or
1919 ** by any temporary tables needed to implement the compound select.
1920 ** Attach the KeyInfo structure to all temporary tables. Invoke the
1921 ** ORDER BY processing if there is an ORDER BY clause.
1922 **
1923 ** This section is run by the right-most SELECT statement only.
1924 ** SELECT statements to the left always skip this part. The right-most
1925 ** SELECT might also skip this part if it has no ORDER BY clause and
1926 ** no temp tables are required.
1927 */
1928 if( pOrderBy || p->usesEphm ){
1929 int i; /* Loop counter */
1930 KeyInfo *pKeyInfo; /* Collating sequence for the result set */
1931 Select *pLoop; /* For looping through SELECT statements */
1932 int nKeyCol; /* Number of entries in pKeyInfo->aCol[] */
1933 CollSeq **apColl; /* For looping through pKeyInfo->aColl[] */
1934 CollSeq **aCopy; /* A copy of pKeyInfo->aColl[] */
1935
1936 assert( p->pRightmost==p );
1937 nKeyCol = nCol + (pOrderBy ? pOrderBy->nExpr : 0);
1938 pKeyInfo = sqliteMalloc(sizeof(*pKeyInfo)+nKeyCol*(sizeof(CollSeq*) + 1));
1939 if( !pKeyInfo ){
1940 rc = SQLITE_NOMEM;
1941 goto multi_select_end;
1942 }
1943
1944 pKeyInfo->enc = ENC(pParse->db);
1945 pKeyInfo->nField = nCol;
1946
1947 for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){
1948 *apColl = multiSelectCollSeq(pParse, p, i);
1949 if( 0==*apColl ){
1950 *apColl = pParse->db->pDfltColl;
1951 }
1952 }
1953
1954 for(pLoop=p; pLoop; pLoop=pLoop->pPrior){
1955 for(i=0; i<2; i++){
1956 int addr = pLoop->addrOpenEphm[i];
1957 if( addr<0 ){
1958 /* If [0] is unused then [1] is also unused. So we can
1959 ** always safely abort as soon as the first unused slot is found */
1960 assert( pLoop->addrOpenEphm[1]<0 );
1961 break;
1962 }
1963 sqlite3VdbeChangeP2(v, addr, nCol);
1964 sqlite3VdbeChangeP3(v, addr, (char*)pKeyInfo, P3_KEYINFO);
1965 pLoop->addrOpenEphm[i] = -1;
1966 }
1967 }
1968
1969 if( pOrderBy ){
1970 struct ExprList_item *pOTerm = pOrderBy->a;
1971 int nOrderByExpr = pOrderBy->nExpr;
1972 int addr;
1973 u8 *pSortOrder;
1974
1975 /* Reuse the same pKeyInfo for the ORDER BY as was used above for
1976 ** the compound select statements. Except we have to change out the
1977 ** pKeyInfo->aColl[] values. Some of the aColl[] values will be
1978 ** reused when constructing the pKeyInfo for the ORDER BY, so make
1979 ** a copy. Sufficient space to hold both the nCol entries for
1980 ** the compound select and the nOrderbyExpr entries for the ORDER BY
1981 ** was allocated above. But we need to move the compound select
1982 ** entries out of the way before constructing the ORDER BY entries.
1983 ** Move the compound select entries into aCopy[] where they can be
1984 ** accessed and reused when constructing the ORDER BY entries.
1985 ** Because nCol might be greater than or less than nOrderByExpr
1986 ** we have to use memmove() when doing the copy.
1987 */
1988 aCopy = &pKeyInfo->aColl[nOrderByExpr];
1989 pSortOrder = pKeyInfo->aSortOrder = (u8*)&aCopy[nCol];
1990 memmove(aCopy, pKeyInfo->aColl, nCol*sizeof(CollSeq*));
1991
1992 apColl = pKeyInfo->aColl;
1993 for(i=0; i<nOrderByExpr; i++, pOTerm++, apColl++, pSortOrder++){
1994 Expr *pExpr = pOTerm->pExpr;
1995 if( (pExpr->flags & EP_ExpCollate) ){
1996 assert( pExpr->pColl!=0 );
1997 *apColl = pExpr->pColl;
1998 }else{
1999 *apColl = aCopy[pExpr->iColumn];
2000 }
2001 *pSortOrder = pOTerm->sortOrder;
2002 }
2003 assert( p->pRightmost==p );
2004 assert( p->addrOpenEphm[2]>=0 );
2005 addr = p->addrOpenEphm[2];
2006 sqlite3VdbeChangeP2(v, addr, p->pOrderBy->nExpr+2);
2007 pKeyInfo->nField = nOrderByExpr;
2008 sqlite3VdbeChangeP3(v, addr, (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
2009 pKeyInfo = 0;
2010 generateSortTail(pParse, p, v, p->pEList->nExpr, eDest, iParm);
2011 }
2012
2013 sqliteFree(pKeyInfo);
2014 }
2015
2016multi_select_end:
2017 return rc;
2018}
2019#endif /* SQLITE_OMIT_COMPOUND_SELECT */
2020
2021#ifndef SQLITE_OMIT_VIEW
2022/*
2023** Scan through the expression pExpr. Replace every reference to
2024** a column in table number iTable with a copy of the iColumn-th
2025** entry in pEList. (But leave references to the ROWID column
2026** unchanged.)
2027**
2028** This routine is part of the flattening procedure. A subquery
2029** whose result set is defined by pEList appears as entry in the
2030** FROM clause of a SELECT such that the VDBE cursor assigned to that
2031** FORM clause entry is iTable. This routine make the necessary
2032** changes to pExpr so that it refers directly to the source table
2033** of the subquery rather the result set of the subquery.
2034*/
2035static void substExprList(ExprList*,int,ExprList*); /* Forward Decl */
2036static void substSelect(Select *, int, ExprList *); /* Forward Decl */
2037static void substExpr(Expr *pExpr, int iTable, ExprList *pEList){
2038 if( pExpr==0 ) return;
2039 if( pExpr->op==TK_COLUMN && pExpr->iTable==iTable ){
2040 if( pExpr->iColumn<0 ){
2041 pExpr->op = TK_NULL;
2042 }else{
2043 Expr *pNew;
2044 assert( pEList!=0 && pExpr->iColumn<pEList->nExpr );
2045 assert( pExpr->pLeft==0 && pExpr->pRight==0 && pExpr->pList==0 );
2046 pNew = pEList->a[pExpr->iColumn].pExpr;
2047 assert( pNew!=0 );
2048 pExpr->op = pNew->op;
2049 assert( pExpr->pLeft==0 );
2050 pExpr->pLeft = sqlite3ExprDup(pNew->pLeft);
2051 assert( pExpr->pRight==0 );
2052 pExpr->pRight = sqlite3ExprDup(pNew->pRight);
2053 assert( pExpr->pList==0 );
2054 pExpr->pList = sqlite3ExprListDup(pNew->pList);
2055 pExpr->iTable = pNew->iTable;
2056 pExpr->pTab = pNew->pTab;
2057 pExpr->iColumn = pNew->iColumn;
2058 pExpr->iAgg = pNew->iAgg;
2059 sqlite3TokenCopy(&pExpr->token, &pNew->token);
2060 sqlite3TokenCopy(&pExpr->span, &pNew->span);
2061 pExpr->pSelect = sqlite3SelectDup(pNew->pSelect);
2062 pExpr->flags = pNew->flags;
2063 }
2064 }else{
2065 substExpr(pExpr->pLeft, iTable, pEList);
2066 substExpr(pExpr->pRight, iTable, pEList);
2067 substSelect(pExpr->pSelect, iTable, pEList);
2068 substExprList(pExpr->pList, iTable, pEList);
2069 }
2070}
2071static void substExprList(ExprList *pList, int iTable, ExprList *pEList){
2072 int i;
2073 if( pList==0 ) return;
2074 for(i=0; i<pList->nExpr; i++){
2075 substExpr(pList->a[i].pExpr, iTable, pEList);
2076 }
2077}
2078static void substSelect(Select *p, int iTable, ExprList *pEList){
2079 if( !p ) return;
2080 substExprList(p->pEList, iTable, pEList);
2081 substExprList(p->pGroupBy, iTable, pEList);
2082 substExprList(p->pOrderBy, iTable, pEList);
2083 substExpr(p->pHaving, iTable, pEList);
2084 substExpr(p->pWhere, iTable, pEList);
2085 substSelect(p->pPrior, iTable, pEList);
2086}
2087#endif /* !defined(SQLITE_OMIT_VIEW) */
2088
2089#ifndef SQLITE_OMIT_VIEW
2090/*
2091** This routine attempts to flatten subqueries in order to speed
2092** execution. It returns 1 if it makes changes and 0 if no flattening
2093** occurs.
2094**
2095** To understand the concept of flattening, consider the following
2096** query:
2097**
2098** SELECT a FROM (SELECT x+y AS a FROM t1 WHERE z<100) WHERE a>5
2099**
2100** The default way of implementing this query is to execute the
2101** subquery first and store the results in a temporary table, then
2102** run the outer query on that temporary table. This requires two
2103** passes over the data. Furthermore, because the temporary table
2104** has no indices, the WHERE clause on the outer query cannot be
2105** optimized.
2106**
2107** This routine attempts to rewrite queries such as the above into
2108** a single flat select, like this:
2109**
2110** SELECT x+y AS a FROM t1 WHERE z<100 AND a>5
2111**
2112** The code generated for this simpification gives the same result
2113** but only has to scan the data once. And because indices might
2114** exist on the table t1, a complete scan of the data might be
2115** avoided.
2116**
2117** Flattening is only attempted if all of the following are true:
2118**
2119** (1) The subquery and the outer query do not both use aggregates.
2120**
2121** (2) The subquery is not an aggregate or the outer query is not a join.
2122**
2123** (3) The subquery is not the right operand of a left outer join, or
2124** the subquery is not itself a join. (Ticket #306)
2125**
2126** (4) The subquery is not DISTINCT or the outer query is not a join.
2127**
2128** (5) The subquery is not DISTINCT or the outer query does not use
2129** aggregates.
2130**
2131** (6) The subquery does not use aggregates or the outer query is not
2132** DISTINCT.
2133**
2134** (7) The subquery has a FROM clause.
2135**
2136** (8) The subquery does not use LIMIT or the outer query is not a join.
2137**
2138** (9) The subquery does not use LIMIT or the outer query does not use
2139** aggregates.
2140**
2141** (10) The subquery does not use aggregates or the outer query does not
2142** use LIMIT.
2143**
2144** (11) The subquery and the outer query do not both have ORDER BY clauses.
2145**
2146** (12) The subquery is not the right term of a LEFT OUTER JOIN or the
2147** subquery has no WHERE clause. (added by ticket #350)
2148**
2149** (13) The subquery and outer query do not both use LIMIT
2150**
2151** (14) The subquery does not use OFFSET
2152**
2153** (15) The outer query is not part of a compound select or the
2154** subquery does not have both an ORDER BY and a LIMIT clause.
2155** (See ticket #2339)
2156**
2157** In this routine, the "p" parameter is a pointer to the outer query.
2158** The subquery is p->pSrc->a[iFrom]. isAgg is true if the outer query
2159** uses aggregates and subqueryIsAgg is true if the subquery uses aggregates.
2160**
2161** If flattening is not attempted, this routine is a no-op and returns 0.
2162** If flattening is attempted this routine returns 1.
2163**
2164** All of the expression analysis must occur on both the outer query and
2165** the subquery before this routine runs.
2166*/
2167static int flattenSubquery(
2168 Select *p, /* The parent or outer SELECT statement */
2169 int iFrom, /* Index in p->pSrc->a[] of the inner subquery */
2170 int isAgg, /* True if outer SELECT uses aggregate functions */
2171 int subqueryIsAgg /* True if the subquery uses aggregate functions */
2172){
2173 Select *pSub; /* The inner query or "subquery" */
2174 SrcList *pSrc; /* The FROM clause of the outer query */
2175 SrcList *pSubSrc; /* The FROM clause of the subquery */
2176 ExprList *pList; /* The result set of the outer query */
2177 int iParent; /* VDBE cursor number of the pSub result set temp table */
2178 int i; /* Loop counter */
2179 Expr *pWhere; /* The WHERE clause */
2180 struct SrcList_item *pSubitem; /* The subquery */
2181
2182 /* Check to see if flattening is permitted. Return 0 if not.
2183 */
2184 if( p==0 ) return 0;
2185 pSrc = p->pSrc;
2186 assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
2187 pSubitem = &pSrc->a[iFrom];
2188 pSub = pSubitem->pSelect;
2189 assert( pSub!=0 );
2190 if( isAgg && subqueryIsAgg ) return 0; /* Restriction (1) */
2191 if( subqueryIsAgg && pSrc->nSrc>1 ) return 0; /* Restriction (2) */
2192 pSubSrc = pSub->pSrc;
2193 assert( pSubSrc );
2194 /* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
2195 ** not arbitrary expresssions, we allowed some combining of LIMIT and OFFSET
2196 ** because they could be computed at compile-time. But when LIMIT and OFFSET
2197 ** became arbitrary expressions, we were forced to add restrictions (13)
2198 ** and (14). */
2199 if( pSub->pLimit && p->pLimit ) return 0; /* Restriction (13) */
2200 if( pSub->pOffset ) return 0; /* Restriction (14) */
2201 if( p->pRightmost && pSub->pLimit && pSub->pOrderBy ){
2202 return 0; /* Restriction (15) */
2203 }
2204 if( pSubSrc->nSrc==0 ) return 0; /* Restriction (7) */
2205 if( (pSub->isDistinct || pSub->pLimit)
2206 && (pSrc->nSrc>1 || isAgg) ){ /* Restrictions (4)(5)(8)(9) */
2207 return 0;
2208 }
2209 if( p->isDistinct && subqueryIsAgg ) return 0; /* Restriction (6) */
2210 if( (p->disallowOrderBy || p->pOrderBy) && pSub->pOrderBy ){
2211 return 0; /* Restriction (11) */
2212 }
2213
2214 /* Restriction 3: If the subquery is a join, make sure the subquery is
2215 ** not used as the right operand of an outer join. Examples of why this
2216 ** is not allowed:
2217 **
2218 ** t1 LEFT OUTER JOIN (t2 JOIN t3)
2219 **
2220 ** If we flatten the above, we would get
2221 **
2222 ** (t1 LEFT OUTER JOIN t2) JOIN t3
2223 **
2224 ** which is not at all the same thing.
2225 */
2226 if( pSubSrc->nSrc>1 && (pSubitem->jointype & JT_OUTER)!=0 ){
2227 return 0;
2228 }
2229
2230 /* Restriction 12: If the subquery is the right operand of a left outer
2231 ** join, make sure the subquery has no WHERE clause.
2232 ** An examples of why this is not allowed:
2233 **
2234 ** t1 LEFT OUTER JOIN (SELECT * FROM t2 WHERE t2.x>0)
2235 **
2236 ** If we flatten the above, we would get
2237 **
2238 ** (t1 LEFT OUTER JOIN t2) WHERE t2.x>0
2239 **
2240 ** But the t2.x>0 test will always fail on a NULL row of t2, which
2241 ** effectively converts the OUTER JOIN into an INNER JOIN.
2242 */
2243 if( (pSubitem->jointype & JT_OUTER)!=0 && pSub->pWhere!=0 ){
2244 return 0;
2245 }
2246
2247 /* If we reach this point, it means flattening is permitted for the
2248 ** iFrom-th entry of the FROM clause in the outer query.
2249 */
2250
2251 /* Move all of the FROM elements of the subquery into the
2252 ** the FROM clause of the outer query. Before doing this, remember
2253 ** the cursor number for the original outer query FROM element in
2254 ** iParent. The iParent cursor will never be used. Subsequent code
2255 ** will scan expressions looking for iParent references and replace
2256 ** those references with expressions that resolve to the subquery FROM
2257 ** elements we are now copying in.
2258 */
2259 iParent = pSubitem->iCursor;
2260 {
2261 int nSubSrc = pSubSrc->nSrc;
2262 int jointype = pSubitem->jointype;
2263
2264 sqlite3DeleteTable(pSubitem->pTab);
2265 sqliteFree(pSubitem->zDatabase);
2266 sqliteFree(pSubitem->zName);
2267 sqliteFree(pSubitem->zAlias);
2268 if( nSubSrc>1 ){
2269 int extra = nSubSrc - 1;
2270 for(i=1; i<nSubSrc; i++){
2271 pSrc = sqlite3SrcListAppend(pSrc, 0, 0);
2272 }
2273 p->pSrc = pSrc;
2274 for(i=pSrc->nSrc-1; i-extra>=iFrom; i--){
2275 pSrc->a[i] = pSrc->a[i-extra];
2276 }
2277 }
2278 for(i=0; i<nSubSrc; i++){
2279 pSrc->a[i+iFrom] = pSubSrc->a[i];
2280 memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i]));
2281 }
2282 pSrc->a[iFrom].jointype = jointype;
2283 }
2284
2285 /* Now begin substituting subquery result set expressions for
2286 ** references to the iParent in the outer query.
2287 **
2288 ** Example:
2289 **
2290 ** SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b;
2291 ** \ \_____________ subquery __________/ /
2292 ** \_____________________ outer query ______________________________/
2293 **
2294 ** We look at every expression in the outer query and every place we see
2295 ** "a" we substitute "x*3" and every place we see "b" we substitute "y+10".
2296 */
2297 pList = p->pEList;
2298 for(i=0; i<pList->nExpr; i++){
2299 Expr *pExpr;
2300 if( pList->a[i].zName==0 && (pExpr = pList->a[i].pExpr)->span.z!=0 ){
2301 pList->a[i].zName = sqliteStrNDup((char*)pExpr->span.z, pExpr->span.n);
2302 }
2303 }
2304 substExprList(p->pEList, iParent, pSub->pEList);
2305 if( isAgg ){
2306 substExprList(p->pGroupBy, iParent, pSub->pEList);
2307 substExpr(p->pHaving, iParent, pSub->pEList);
2308 }
2309 if( pSub->pOrderBy ){
2310 assert( p->pOrderBy==0 );
2311 p->pOrderBy = pSub->pOrderBy;
2312 pSub->pOrderBy = 0;
2313 }else if( p->pOrderBy ){
2314 substExprList(p->pOrderBy, iParent, pSub->pEList);
2315 }
2316 if( pSub->pWhere ){
2317 pWhere = sqlite3ExprDup(pSub->pWhere);
2318 }else{
2319 pWhere = 0;
2320 }
2321 if( subqueryIsAgg ){
2322 assert( p->pHaving==0 );
2323 p->pHaving = p->pWhere;
2324 p->pWhere = pWhere;
2325 substExpr(p->pHaving, iParent, pSub->pEList);
2326 p->pHaving = sqlite3ExprAnd(p->pHaving, sqlite3ExprDup(pSub->pHaving));
2327 assert( p->pGroupBy==0 );
2328 p->pGroupBy = sqlite3ExprListDup(pSub->pGroupBy);
2329 }else{
2330 substExpr(p->pWhere, iParent, pSub->pEList);
2331 p->pWhere = sqlite3ExprAnd(p->pWhere, pWhere);
2332 }
2333
2334 /* The flattened query is distinct if either the inner or the
2335 ** outer query is distinct.
2336 */
2337 p->isDistinct = p->isDistinct || pSub->isDistinct;
2338
2339 /*
2340 ** SELECT ... FROM (SELECT ... LIMIT a OFFSET b) LIMIT x OFFSET y;
2341 **
2342 ** One is tempted to try to add a and b to combine the limits. But this
2343 ** does not work if either limit is negative.
2344 */
2345 if( pSub->pLimit ){
2346 p->pLimit = pSub->pLimit;
2347 pSub->pLimit = 0;
2348 }
2349
2350 /* Finially, delete what is left of the subquery and return
2351 ** success.
2352 */
2353 sqlite3SelectDelete(pSub);
2354 return 1;
2355}
2356#endif /* SQLITE_OMIT_VIEW */
2357
2358/*
2359** Analyze the SELECT statement passed in as an argument to see if it
2360** is a simple min() or max() query. If it is and this query can be
2361** satisfied using a single seek to the beginning or end of an index,
2362** then generate the code for this SELECT and return 1. If this is not a
2363** simple min() or max() query, then return 0;
2364**
2365** A simply min() or max() query looks like this:
2366**
2367** SELECT min(a) FROM table;
2368** SELECT max(a) FROM table;
2369**
2370** The query may have only a single table in its FROM argument. There
2371** can be no GROUP BY or HAVING or WHERE clauses. The result set must
2372** be the min() or max() of a single column of the table. The column
2373** in the min() or max() function must be indexed.
2374**
2375** The parameters to this routine are the same as for sqlite3Select().
2376** See the header comment on that routine for additional information.
2377*/
2378static int simpleMinMaxQuery(Parse *pParse, Select *p, int eDest, int iParm){
2379 Expr *pExpr;
2380 int iCol;
2381 Table *pTab;
2382 Index *pIdx;
2383 int base;
2384 Vdbe *v;
2385 int seekOp;
2386 ExprList *pEList, *pList, eList;
2387 struct ExprList_item eListItem;
2388 SrcList *pSrc;
2389 int brk;
2390 int iDb;
2391
2392 /* Check to see if this query is a simple min() or max() query. Return
2393 ** zero if it is not.
2394 */
2395 if( p->pGroupBy || p->pHaving || p->pWhere ) return 0;
2396 pSrc = p->pSrc;
2397 if( pSrc->nSrc!=1 ) return 0;
2398 pEList = p->pEList;
2399 if( pEList->nExpr!=1 ) return 0;
2400 pExpr = pEList->a[0].pExpr;
2401 if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
2402 pList = pExpr->pList;
2403 if( pList==0 || pList->nExpr!=1 ) return 0;
2404 if( pExpr->token.n!=3 ) return 0;
2405 if( sqlite3StrNICmp((char*)pExpr->token.z,"min",3)==0 ){
2406 seekOp = OP_Rewind;
2407 }else if( sqlite3StrNICmp((char*)pExpr->token.z,"max",3)==0 ){
2408 seekOp = OP_Last;
2409 }else{
2410 return 0;
2411 }
2412 pExpr = pList->a[0].pExpr;
2413 if( pExpr->op!=TK_COLUMN ) return 0;
2414 iCol = pExpr->iColumn;
2415 pTab = pSrc->a[0].pTab;
2416
2417 /* This optimization cannot be used with virtual tables. */
2418 if( IsVirtual(pTab) ) return 0;
2419
2420 /* If we get to here, it means the query is of the correct form.
2421 ** Check to make sure we have an index and make pIdx point to the
2422 ** appropriate index. If the min() or max() is on an INTEGER PRIMARY
2423 ** key column, no index is necessary so set pIdx to NULL. If no
2424 ** usable index is found, return 0.
2425 */
2426 if( iCol<0 ){
2427 pIdx = 0;
2428 }else{
2429 CollSeq *pColl = sqlite3ExprCollSeq(pParse, pExpr);
2430 if( pColl==0 ) return 0;
2431 for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
2432 assert( pIdx->nColumn>=1 );
2433 if( pIdx->aiColumn[0]==iCol &&
2434 0==sqlite3StrICmp(pIdx->azColl[0], pColl->zName) ){
2435 break;
2436 }
2437 }
2438 if( pIdx==0 ) return 0;
2439 }
2440
2441 /* Identify column types if we will be using the callback. This
2442 ** step is skipped if the output is going to a table or a memory cell.
2443 ** The column names have already been generated in the calling function.
2444 */
2445 v = sqlite3GetVdbe(pParse);
2446 if( v==0 ) return 0;
2447
2448 /* If the output is destined for a temporary table, open that table.
2449 */
2450 if( eDest==SRT_EphemTab ){
2451 sqlite3VdbeAddOp(v, OP_OpenEphemeral, iParm, 1);
2452 }
2453
2454 /* Generating code to find the min or the max. Basically all we have
2455 ** to do is find the first or the last entry in the chosen index. If
2456 ** the min() or max() is on the INTEGER PRIMARY KEY, then find the first
2457 ** or last entry in the main table.
2458 */
2459 iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
2460 assert( iDb>=0 || pTab->isEphem );
2461 sqlite3CodeVerifySchema(pParse, iDb);
2462 sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
2463 base = pSrc->a[0].iCursor;
2464 brk = sqlite3VdbeMakeLabel(v);
2465 computeLimitRegisters(pParse, p, brk);
2466 if( pSrc->a[0].pSelect==0 ){
2467 sqlite3OpenTable(pParse, base, iDb, pTab, OP_OpenRead);
2468 }
2469 if( pIdx==0 ){
2470 sqlite3VdbeAddOp(v, seekOp, base, 0);
2471 }else{
2472 /* Even though the cursor used to open the index here is closed
2473 ** as soon as a single value has been read from it, allocate it
2474 ** using (pParse->nTab++) to prevent the cursor id from being
2475 ** reused. This is important for statements of the form
2476 ** "INSERT INTO x SELECT max() FROM x".
2477 */
2478 int iIdx;
2479 KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
2480 iIdx = pParse->nTab++;
2481 assert( pIdx->pSchema==pTab->pSchema );
2482 sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
2483 sqlite3VdbeOp3(v, OP_OpenRead, iIdx, pIdx->tnum,
2484 (char*)pKey, P3_KEYINFO_HANDOFF);
2485 if( seekOp==OP_Rewind ){
2486 sqlite3VdbeAddOp(v, OP_Null, 0, 0);
2487 sqlite3VdbeAddOp(v, OP_MakeRecord, 1, 0);
2488 seekOp = OP_MoveGt;
2489 }
2490 sqlite3VdbeAddOp(v, seekOp, iIdx, 0);
2491 sqlite3VdbeAddOp(v, OP_IdxRowid, iIdx, 0);
2492 sqlite3VdbeAddOp(v, OP_Close, iIdx, 0);
2493 sqlite3VdbeAddOp(v, OP_MoveGe, base, 0);
2494 }
2495 eList.nExpr = 1;
2496 memset(&eListItem, 0, sizeof(eListItem));
2497 eList.a = &eListItem;
2498 eList.a[0].pExpr = pExpr;
2499 selectInnerLoop(pParse, p, &eList, 0, 0, 0, -1, eDest, iParm, brk, brk, 0);
2500 sqlite3VdbeResolveLabel(v, brk);
2501 sqlite3VdbeAddOp(v, OP_Close, base, 0);
2502
2503 return 1;
2504}
2505
2506/*
2507** Analyze and ORDER BY or GROUP BY clause in a SELECT statement. Return
2508** the number of errors seen.
2509**
2510** An ORDER BY or GROUP BY is a list of expressions. If any expression
2511** is an integer constant, then that expression is replaced by the
2512** corresponding entry in the result set.
2513*/
2514static int processOrderGroupBy(
2515 NameContext *pNC, /* Name context of the SELECT statement. */
2516 ExprList *pOrderBy, /* The ORDER BY or GROUP BY clause to be processed */
2517 const char *zType /* Either "ORDER" or "GROUP", as appropriate */
2518){
2519 int i;
2520 ExprList *pEList = pNC->pEList; /* The result set of the SELECT */
2521 Parse *pParse = pNC->pParse; /* The result set of the SELECT */
2522 assert( pEList );
2523
2524 if( pOrderBy==0 ) return 0;
2525 if( pOrderBy->nExpr>SQLITE_MAX_COLUMN ){
2526 sqlite3ErrorMsg(pParse, "too many terms in %s BY clause", zType);
2527 return 1;
2528 }
2529 for(i=0; i<pOrderBy->nExpr; i++){
2530 int iCol;
2531 Expr *pE = pOrderBy->a[i].pExpr;
2532 if( sqlite3ExprIsInteger(pE, &iCol) ){
2533 if( iCol>0 && iCol<=pEList->nExpr ){
2534 CollSeq *pColl = pE->pColl;
2535 int flags = pE->flags & EP_ExpCollate;
2536 sqlite3ExprDelete(pE);
2537 pE = pOrderBy->a[i].pExpr = sqlite3ExprDup(pEList->a[iCol-1].pExpr);
2538 if( pColl && flags ){
2539 pE->pColl = pColl;
2540 pE->flags |= flags;
2541 }
2542 }else{
2543 sqlite3ErrorMsg(pParse,
2544 "%s BY column number %d out of range - should be "
2545 "between 1 and %d", zType, iCol, pEList->nExpr);
2546 return 1;
2547 }
2548 }
2549 if( sqlite3ExprResolveNames(pNC, pE) ){
2550 return 1;
2551 }
2552 }
2553 return 0;
2554}
2555
2556/*
2557** This routine resolves any names used in the result set of the
2558** supplied SELECT statement. If the SELECT statement being resolved
2559** is a sub-select, then pOuterNC is a pointer to the NameContext
2560** of the parent SELECT.
2561*/
2562int sqlite3SelectResolve(
2563 Parse *pParse, /* The parser context */
2564 Select *p, /* The SELECT statement being coded. */
2565 NameContext *pOuterNC /* The outer name context. May be NULL. */
2566){
2567 ExprList *pEList; /* Result set. */
2568 int i; /* For-loop variable used in multiple places */
2569 NameContext sNC; /* Local name-context */
2570 ExprList *pGroupBy; /* The group by clause */
2571
2572 /* If this routine has run before, return immediately. */
2573 if( p->isResolved ){
2574 assert( !pOuterNC );
2575 return SQLITE_OK;
2576 }
2577 p->isResolved = 1;
2578
2579 /* If there have already been errors, do nothing. */
2580 if( pParse->nErr>0 ){
2581 return SQLITE_ERROR;
2582 }
2583
2584 /* Prepare the select statement. This call will allocate all cursors
2585 ** required to handle the tables and subqueries in the FROM clause.
2586 */
2587 if( prepSelectStmt(pParse, p) ){
2588 return SQLITE_ERROR;
2589 }
2590
2591 /* Resolve the expressions in the LIMIT and OFFSET clauses. These
2592 ** are not allowed to refer to any names, so pass an empty NameContext.
2593 */
2594 memset(&sNC, 0, sizeof(sNC));
2595 sNC.pParse = pParse;
2596 if( sqlite3ExprResolveNames(&sNC, p->pLimit) ||
2597 sqlite3ExprResolveNames(&sNC, p->pOffset) ){
2598 return SQLITE_ERROR;
2599 }
2600
2601 /* Set up the local name-context to pass to ExprResolveNames() to
2602 ** resolve the expression-list.
2603 */
2604 sNC.allowAgg = 1;
2605 sNC.pSrcList = p->pSrc;
2606 sNC.pNext = pOuterNC;
2607
2608 /* Resolve names in the result set. */
2609 pEList = p->pEList;
2610 if( !pEList ) return SQLITE_ERROR;
2611 for(i=0; i<pEList->nExpr; i++){
2612 Expr *pX = pEList->a[i].pExpr;
2613 if( sqlite3ExprResolveNames(&sNC, pX) ){
2614 return SQLITE_ERROR;
2615 }
2616 }
2617
2618 /* If there are no aggregate functions in the result-set, and no GROUP BY
2619 ** expression, do not allow aggregates in any of the other expressions.
2620 */
2621 assert( !p->isAgg );
2622 pGroupBy = p->pGroupBy;
2623 if( pGroupBy || sNC.hasAgg ){
2624 p->isAgg = 1;
2625 }else{
2626 sNC.allowAgg = 0;
2627 }
2628
2629 /* If a HAVING clause is present, then there must be a GROUP BY clause.
2630 */
2631 if( p->pHaving && !pGroupBy ){
2632 sqlite3ErrorMsg(pParse, "a GROUP BY clause is required before HAVING");
2633 return SQLITE_ERROR;
2634 }
2635
2636 /* Add the expression list to the name-context before parsing the
2637 ** other expressions in the SELECT statement. This is so that
2638 ** expressions in the WHERE clause (etc.) can refer to expressions by
2639 ** aliases in the result set.
2640 **
2641 ** Minor point: If this is the case, then the expression will be
2642 ** re-evaluated for each reference to it.
2643 */
2644 sNC.pEList = p->pEList;
2645 if( sqlite3ExprResolveNames(&sNC, p->pWhere) ||
2646 sqlite3ExprResolveNames(&sNC, p->pHaving) ){
2647 return SQLITE_ERROR;
2648 }
2649 if( p->pPrior==0 ){
2650 if( processOrderGroupBy(&sNC, p->pOrderBy, "ORDER") ||
2651 processOrderGroupBy(&sNC, pGroupBy, "GROUP") ){
2652 return SQLITE_ERROR;
2653 }
2654 }
2655
2656 if( sqlite3MallocFailed() ){
2657 return SQLITE_NOMEM;
2658 }
2659
2660 /* Make sure the GROUP BY clause does not contain aggregate functions.
2661 */
2662 if( pGroupBy ){
2663 struct ExprList_item *pItem;
2664
2665 for(i=0, pItem=pGroupBy->a; i<pGroupBy->nExpr; i++, pItem++){
2666 if( ExprHasProperty(pItem->pExpr, EP_Agg) ){
2667 sqlite3ErrorMsg(pParse, "aggregate functions are not allowed in "
2668 "the GROUP BY clause");
2669 return SQLITE_ERROR;
2670 }
2671 }
2672 }
2673
2674 /* If this is one SELECT of a compound, be sure to resolve names
2675 ** in the other SELECTs.
2676 */
2677 if( p->pPrior ){
2678 return sqlite3SelectResolve(pParse, p->pPrior, pOuterNC);
2679 }else{
2680 return SQLITE_OK;
2681 }
2682}
2683
2684/*
2685** Reset the aggregate accumulator.
2686**
2687** The aggregate accumulator is a set of memory cells that hold
2688** intermediate results while calculating an aggregate. This
2689** routine simply stores NULLs in all of those memory cells.
2690*/
2691static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){
2692 Vdbe *v = pParse->pVdbe;
2693 int i;
2694 struct AggInfo_func *pFunc;
2695 if( pAggInfo->nFunc+pAggInfo->nColumn==0 ){
2696 return;
2697 }
2698 for(i=0; i<pAggInfo->nColumn; i++){
2699 sqlite3VdbeAddOp(v, OP_MemNull, pAggInfo->aCol[i].iMem, 0);
2700 }
2701 for(pFunc=pAggInfo->aFunc, i=0; i<pAggInfo->nFunc; i++, pFunc++){
2702 sqlite3VdbeAddOp(v, OP_MemNull, pFunc->iMem, 0);
2703 if( pFunc->iDistinct>=0 ){
2704 Expr *pE = pFunc->pExpr;
2705 if( pE->pList==0 || pE->pList->nExpr!=1 ){
2706 sqlite3ErrorMsg(pParse, "DISTINCT in aggregate must be followed "
2707 "by an expression");
2708 pFunc->iDistinct = -1;
2709 }else{
2710 KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pE->pList);
2711 sqlite3VdbeOp3(v, OP_OpenEphemeral, pFunc->iDistinct, 0,
2712 (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
2713 }
2714 }
2715 }
2716}
2717
2718/*
2719** Invoke the OP_AggFinalize opcode for every aggregate function
2720** in the AggInfo structure.
2721*/
2722static void finalizeAggFunctions(Parse *pParse, AggInfo *pAggInfo){
2723 Vdbe *v = pParse->pVdbe;
2724 int i;
2725 struct AggInfo_func *pF;
2726 for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
2727 ExprList *pList = pF->pExpr->pList;
2728 sqlite3VdbeOp3(v, OP_AggFinal, pF->iMem, pList ? pList->nExpr : 0,
2729 (void*)pF->pFunc, P3_FUNCDEF);
2730 }
2731}
2732
2733/*
2734** Update the accumulator memory cells for an aggregate based on
2735** the current cursor position.
2736*/
2737static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
2738 Vdbe *v = pParse->pVdbe;
2739 int i;
2740 struct AggInfo_func *pF;
2741 struct AggInfo_col *pC;
2742
2743 pAggInfo->directMode = 1;
2744 for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
2745 int nArg;
2746 int addrNext = 0;
2747 ExprList *pList = pF->pExpr->pList;
2748 if( pList ){
2749 nArg = pList->nExpr;
2750 sqlite3ExprCodeExprList(pParse, pList);
2751 }else{
2752 nArg = 0;
2753 }
2754 if( pF->iDistinct>=0 ){
2755 addrNext = sqlite3VdbeMakeLabel(v);
2756 assert( nArg==1 );
2757 codeDistinct(v, pF->iDistinct, addrNext, 1);
2758 }
2759 if( pF->pFunc->needCollSeq ){
2760 CollSeq *pColl = 0;
2761 struct ExprList_item *pItem;
2762 int j;
2763 assert( pList!=0 ); /* pList!=0 if pF->pFunc->needCollSeq is true */
2764 for(j=0, pItem=pList->a; !pColl && j<nArg; j++, pItem++){
2765 pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
2766 }
2767 if( !pColl ){
2768 pColl = pParse->db->pDfltColl;
2769 }
2770 sqlite3VdbeOp3(v, OP_CollSeq, 0, 0, (char *)pColl, P3_COLLSEQ);
2771 }
2772 sqlite3VdbeOp3(v, OP_AggStep, pF->iMem, nArg, (void*)pF->pFunc, P3_FUNCDEF);
2773 if( addrNext ){
2774 sqlite3VdbeResolveLabel(v, addrNext);
2775 }
2776 }
2777 for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
2778 sqlite3ExprCode(pParse, pC->pExpr);
2779 sqlite3VdbeAddOp(v, OP_MemStore, pC->iMem, 1);
2780 }
2781 pAggInfo->directMode = 0;
2782}
2783
2784
2785/*
2786** Generate code for the given SELECT statement.
2787**
2788** The results are distributed in various ways depending on the
2789** value of eDest and iParm.
2790**
2791** eDest Value Result
2792** ------------ -------------------------------------------
2793** SRT_Callback Invoke the callback for each row of the result.
2794**
2795** SRT_Mem Store first result in memory cell iParm
2796**
2797** SRT_Set Store results as keys of table iParm.
2798**
2799** SRT_Union Store results as a key in a temporary table iParm
2800**
2801** SRT_Except Remove results from the temporary table iParm.
2802**
2803** SRT_Table Store results in temporary table iParm
2804**
2805** The table above is incomplete. Additional eDist value have be added
2806** since this comment was written. See the selectInnerLoop() function for
2807** a complete listing of the allowed values of eDest and their meanings.
2808**
2809** This routine returns the number of errors. If any errors are
2810** encountered, then an appropriate error message is left in
2811** pParse->zErrMsg.
2812**
2813** This routine does NOT free the Select structure passed in. The
2814** calling function needs to do that.
2815**
2816** The pParent, parentTab, and *pParentAgg fields are filled in if this
2817** SELECT is a subquery. This routine may try to combine this SELECT
2818** with its parent to form a single flat query. In so doing, it might
2819** change the parent query from a non-aggregate to an aggregate query.
2820** For that reason, the pParentAgg flag is passed as a pointer, so it
2821** can be changed.
2822**
2823** Example 1: The meaning of the pParent parameter.
2824**
2825** SELECT * FROM t1 JOIN (SELECT x, count(*) FROM t2) JOIN t3;
2826** \ \_______ subquery _______/ /
2827** \ /
2828** \____________________ outer query ___________________/
2829**
2830** This routine is called for the outer query first. For that call,
2831** pParent will be NULL. During the processing of the outer query, this
2832** routine is called recursively to handle the subquery. For the recursive
2833** call, pParent will point to the outer query. Because the subquery is
2834** the second element in a three-way join, the parentTab parameter will
2835** be 1 (the 2nd value of a 0-indexed array.)
2836*/
2837int sqlite3Select(
2838 Parse *pParse, /* The parser context */
2839 Select *p, /* The SELECT statement being coded. */
2840 int eDest, /* How to dispose of the results */
2841 int iParm, /* A parameter used by the eDest disposal method */
2842 Select *pParent, /* Another SELECT for which this is a sub-query */
2843 int parentTab, /* Index in pParent->pSrc of this query */
2844 int *pParentAgg, /* True if pParent uses aggregate functions */
2845 char *aff /* If eDest is SRT_Union, the affinity string */
2846){
2847 int i, j; /* Loop counters */
2848 WhereInfo *pWInfo; /* Return from sqlite3WhereBegin() */
2849 Vdbe *v; /* The virtual machine under construction */
2850 int isAgg; /* True for select lists like "count(*)" */
2851 ExprList *pEList; /* List of columns to extract. */
2852 SrcList *pTabList; /* List of tables to select from */
2853 Expr *pWhere; /* The WHERE clause. May be NULL */
2854 ExprList *pOrderBy; /* The ORDER BY clause. May be NULL */
2855 ExprList *pGroupBy; /* The GROUP BY clause. May be NULL */
2856 Expr *pHaving; /* The HAVING clause. May be NULL */
2857 int isDistinct; /* True if the DISTINCT keyword is present */
2858 int distinct; /* Table to use for the distinct set */
2859 int rc = 1; /* Value to return from this function */
2860 int addrSortIndex; /* Address of an OP_OpenEphemeral instruction */
2861 AggInfo sAggInfo; /* Information used by aggregate queries */
2862 int iEnd; /* Address of the end of the query */
2863
2864 if( p==0 || sqlite3MallocFailed() || pParse->nErr ){
2865 return 1;
2866 }
2867 if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
2868 memset(&sAggInfo, 0, sizeof(sAggInfo));
2869
2870#ifndef SQLITE_OMIT_COMPOUND_SELECT
2871 /* If there is are a sequence of queries, do the earlier ones first.
2872 */
2873 if( p->pPrior ){
2874 if( p->pRightmost==0 ){
2875 Select *pLoop;
2876 int cnt = 0;
2877 for(pLoop=p; pLoop; pLoop=pLoop->pPrior, cnt++){
2878 pLoop->pRightmost = p;
2879 }
2880 if( SQLITE_MAX_COMPOUND_SELECT>0 && cnt>SQLITE_MAX_COMPOUND_SELECT ){
2881 sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
2882 return 1;
2883 }
2884 }
2885 return multiSelect(pParse, p, eDest, iParm, aff);
2886 }
2887#endif
2888
2889 pOrderBy = p->pOrderBy;
2890 if( IgnorableOrderby(eDest) ){
2891 p->pOrderBy = 0;
2892 }
2893 if( sqlite3SelectResolve(pParse, p, 0) ){
2894 goto select_end;
2895 }
2896 p->pOrderBy = pOrderBy;
2897
2898 /* Make local copies of the parameters for this query.
2899 */
2900 pTabList = p->pSrc;
2901 pWhere = p->pWhere;
2902 pGroupBy = p->pGroupBy;
2903 pHaving = p->pHaving;
2904 isAgg = p->isAgg;
2905 isDistinct = p->isDistinct;
2906 pEList = p->pEList;
2907 if( pEList==0 ) goto select_end;
2908
2909 /*
2910 ** Do not even attempt to generate any code if we have already seen
2911 ** errors before this routine starts.
2912 */
2913 if( pParse->nErr>0 ) goto select_end;
2914
2915 /* If writing to memory or generating a set
2916 ** only a single column may be output.
2917 */
2918#ifndef SQLITE_OMIT_SUBQUERY
2919 if( checkForMultiColumnSelectError(pParse, eDest, pEList->nExpr) ){
2920 goto select_end;
2921 }
2922#endif
2923
2924 /* ORDER BY is ignored for some destinations.
2925 */
2926 if( IgnorableOrderby(eDest) ){
2927 pOrderBy = 0;
2928 }
2929
2930 /* Begin generating code.
2931 */
2932 v = sqlite3GetVdbe(pParse);
2933 if( v==0 ) goto select_end;
2934
2935 /* Generate code for all sub-queries in the FROM clause
2936 */
2937#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
2938 for(i=0; i<pTabList->nSrc; i++){
2939 const char *zSavedAuthContext = 0;
2940 int needRestoreContext;
2941 struct SrcList_item *pItem = &pTabList->a[i];
2942
2943 if( pItem->pSelect==0 || pItem->isPopulated ) continue;
2944 if( pItem->zName!=0 ){
2945 zSavedAuthContext = pParse->zAuthContext;
2946 pParse->zAuthContext = pItem->zName;
2947 needRestoreContext = 1;
2948 }else{
2949 needRestoreContext = 0;
2950 }
2951#if SQLITE_MAX_EXPR_DEPTH>0
2952 /* Increment Parse.nHeight by the height of the largest expression
2953 ** tree refered to by this, the parent select. The child select
2954 ** may contain expression trees of at most
2955 ** (SQLITE_MAX_EXPR_DEPTH-Parse.nHeight) height. This is a bit
2956 ** more conservative than necessary, but much easier than enforcing
2957 ** an exact limit.
2958 */
2959 pParse->nHeight += sqlite3SelectExprHeight(p);
2960#endif
2961 sqlite3Select(pParse, pItem->pSelect, SRT_EphemTab,
2962 pItem->iCursor, p, i, &isAgg, 0);
2963#if SQLITE_MAX_EXPR_DEPTH>0
2964 pParse->nHeight -= sqlite3SelectExprHeight(p);
2965#endif
2966 if( needRestoreContext ){
2967 pParse->zAuthContext = zSavedAuthContext;
2968 }
2969 pTabList = p->pSrc;
2970 pWhere = p->pWhere;
2971 if( !IgnorableOrderby(eDest) ){
2972 pOrderBy = p->pOrderBy;
2973 }
2974 pGroupBy = p->pGroupBy;
2975 pHaving = p->pHaving;
2976 isDistinct = p->isDistinct;
2977 }
2978#endif
2979
2980 /* Check for the special case of a min() or max() function by itself
2981 ** in the result set.
2982 */
2983 if( simpleMinMaxQuery(pParse, p, eDest, iParm) ){
2984 rc = 0;
2985 goto select_end;
2986 }
2987
2988 /* Check to see if this is a subquery that can be "flattened" into its parent.
2989 ** If flattening is a possiblity, do so and return immediately.
2990 */
2991#ifndef SQLITE_OMIT_VIEW
2992 if( pParent && pParentAgg &&
2993 flattenSubquery(pParent, parentTab, *pParentAgg, isAgg) ){
2994 if( isAgg ) *pParentAgg = 1;
2995 goto select_end;
2996 }
2997#endif
2998
2999 /* If there is an ORDER BY clause, then this sorting
3000 ** index might end up being unused if the data can be
3001 ** extracted in pre-sorted order. If that is the case, then the
3002 ** OP_OpenEphemeral instruction will be changed to an OP_Noop once
3003 ** we figure out that the sorting index is not needed. The addrSortIndex
3004 ** variable is used to facilitate that change.
3005 */
3006 if( pOrderBy ){
3007 KeyInfo *pKeyInfo;
3008 if( pParse->nErr ){
3009 goto select_end;
3010 }
3011 pKeyInfo = keyInfoFromExprList(pParse, pOrderBy);
3012 pOrderBy->iECursor = pParse->nTab++;
3013 p->addrOpenEphm[2] = addrSortIndex =
3014 sqlite3VdbeOp3(v, OP_OpenEphemeral, pOrderBy->iECursor, pOrderBy->nExpr+2, (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
3015 }else{
3016 addrSortIndex = -1;
3017 }
3018
3019 /* If the output is destined for a temporary table, open that table.
3020 */
3021 if( eDest==SRT_EphemTab ){
3022 sqlite3VdbeAddOp(v, OP_OpenEphemeral, iParm, pEList->nExpr);
3023 }
3024
3025 /* Set the limiter.
3026 */
3027 iEnd = sqlite3VdbeMakeLabel(v);
3028 computeLimitRegisters(pParse, p, iEnd);
3029
3030 /* Open a virtual index to use for the distinct set.
3031 */
3032 if( isDistinct ){
3033 KeyInfo *pKeyInfo;
3034 distinct = pParse->nTab++;
3035 pKeyInfo = keyInfoFromExprList(pParse, p->pEList);
3036 sqlite3VdbeOp3(v, OP_OpenEphemeral, distinct, 0,
3037 (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
3038 }else{
3039 distinct = -1;
3040 }
3041
3042 /* Aggregate and non-aggregate queries are handled differently */
3043 if( !isAgg && pGroupBy==0 ){
3044 /* This case is for non-aggregate queries
3045 ** Begin the database scan
3046 */
3047 pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pOrderBy);
3048 if( pWInfo==0 ) goto select_end;
3049
3050 /* If sorting index that was created by a prior OP_OpenEphemeral
3051 ** instruction ended up not being needed, then change the OP_OpenEphemeral
3052 ** into an OP_Noop.
3053 */
3054 if( addrSortIndex>=0 && pOrderBy==0 ){
3055 sqlite3VdbeChangeToNoop(v, addrSortIndex, 1);
3056 p->addrOpenEphm[2] = -1;
3057 }
3058
3059 /* Use the standard inner loop
3060 */
3061 if( selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, eDest,
3062 iParm, pWInfo->iContinue, pWInfo->iBreak, aff) ){
3063 goto select_end;
3064 }
3065
3066 /* End the database scan loop.
3067 */
3068 sqlite3WhereEnd(pWInfo);
3069 }else{
3070 /* This is the processing for aggregate queries */
3071 NameContext sNC; /* Name context for processing aggregate information */
3072 int iAMem; /* First Mem address for storing current GROUP BY */
3073 int iBMem; /* First Mem address for previous GROUP BY */
3074 int iUseFlag; /* Mem address holding flag indicating that at least
3075 ** one row of the input to the aggregator has been
3076 ** processed */
3077 int iAbortFlag; /* Mem address which causes query abort if positive */
3078 int groupBySort; /* Rows come from source in GROUP BY order */
3079
3080
3081 /* The following variables hold addresses or labels for parts of the
3082 ** virtual machine program we are putting together */
3083 int addrOutputRow; /* Start of subroutine that outputs a result row */
3084 int addrSetAbort; /* Set the abort flag and return */
3085 int addrInitializeLoop; /* Start of code that initializes the input loop */
3086 int addrTopOfLoop; /* Top of the input loop */
3087 int addrGroupByChange; /* Code that runs when any GROUP BY term changes */
3088 int addrProcessRow; /* Code to process a single input row */
3089 int addrEnd; /* End of all processing */
3090 int addrSortingIdx; /* The OP_OpenEphemeral for the sorting index */
3091 int addrReset; /* Subroutine for resetting the accumulator */
3092
3093 addrEnd = sqlite3VdbeMakeLabel(v);
3094
3095 /* Convert TK_COLUMN nodes into TK_AGG_COLUMN and make entries in
3096 ** sAggInfo for all TK_AGG_FUNCTION nodes in expressions of the
3097 ** SELECT statement.
3098 */
3099 memset(&sNC, 0, sizeof(sNC));
3100 sNC.pParse = pParse;
3101 sNC.pSrcList = pTabList;
3102 sNC.pAggInfo = &sAggInfo;
3103 sAggInfo.nSortingColumn = pGroupBy ? pGroupBy->nExpr+1 : 0;
3104 sAggInfo.pGroupBy = pGroupBy;
3105 if( sqlite3ExprAnalyzeAggList(&sNC, pEList) ){
3106 goto select_end;
3107 }
3108 if( sqlite3ExprAnalyzeAggList(&sNC, pOrderBy) ){
3109 goto select_end;
3110 }
3111 if( pHaving && sqlite3ExprAnalyzeAggregates(&sNC, pHaving) ){
3112 goto select_end;
3113 }
3114 sAggInfo.nAccumulator = sAggInfo.nColumn;
3115 for(i=0; i<sAggInfo.nFunc; i++){
3116 if( sqlite3ExprAnalyzeAggList(&sNC, sAggInfo.aFunc[i].pExpr->pList) ){
3117 goto select_end;
3118 }
3119 }
3120 if( sqlite3MallocFailed() ) goto select_end;
3121
3122 /* Processing for aggregates with GROUP BY is very different and
3123 ** much more complex tha aggregates without a GROUP BY.
3124 */
3125 if( pGroupBy ){
3126 KeyInfo *pKeyInfo; /* Keying information for the group by clause */
3127
3128 /* Create labels that we will be needing
3129 */
3130
3131 addrInitializeLoop = sqlite3VdbeMakeLabel(v);
3132 addrGroupByChange = sqlite3VdbeMakeLabel(v);
3133 addrProcessRow = sqlite3VdbeMakeLabel(v);
3134
3135 /* If there is a GROUP BY clause we might need a sorting index to
3136 ** implement it. Allocate that sorting index now. If it turns out
3137 ** that we do not need it after all, the OpenEphemeral instruction
3138 ** will be converted into a Noop.
3139 */
3140 sAggInfo.sortingIdx = pParse->nTab++;
3141 pKeyInfo = keyInfoFromExprList(pParse, pGroupBy);
3142 addrSortingIdx =
3143 sqlite3VdbeOp3(v, OP_OpenEphemeral, sAggInfo.sortingIdx,
3144 sAggInfo.nSortingColumn,
3145 (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
3146
3147 /* Initialize memory locations used by GROUP BY aggregate processing
3148 */
3149 iUseFlag = pParse->nMem++;
3150 iAbortFlag = pParse->nMem++;
3151 iAMem = pParse->nMem;
3152 pParse->nMem += pGroupBy->nExpr;
3153 iBMem = pParse->nMem;
3154 pParse->nMem += pGroupBy->nExpr;
3155 sqlite3VdbeAddOp(v, OP_MemInt, 0, iAbortFlag);
3156 VdbeComment((v, "# clear abort flag"));
3157 sqlite3VdbeAddOp(v, OP_MemInt, 0, iUseFlag);
3158 VdbeComment((v, "# indicate accumulator empty"));
3159 sqlite3VdbeAddOp(v, OP_Goto, 0, addrInitializeLoop);
3160
3161 /* Generate a subroutine that outputs a single row of the result
3162 ** set. This subroutine first looks at the iUseFlag. If iUseFlag
3163 ** is less than or equal to zero, the subroutine is a no-op. If
3164 ** the processing calls for the query to abort, this subroutine
3165 ** increments the iAbortFlag memory location before returning in
3166 ** order to signal the caller to abort.
3167 */
3168 addrSetAbort = sqlite3VdbeCurrentAddr(v);
3169 sqlite3VdbeAddOp(v, OP_MemInt, 1, iAbortFlag);
3170 VdbeComment((v, "# set abort flag"));
3171 sqlite3VdbeAddOp(v, OP_Return, 0, 0);
3172 addrOutputRow = sqlite3VdbeCurrentAddr(v);
3173 sqlite3VdbeAddOp(v, OP_IfMemPos, iUseFlag, addrOutputRow+2);
3174 VdbeComment((v, "# Groupby result generator entry point"));
3175 sqlite3VdbeAddOp(v, OP_Return, 0, 0);
3176 finalizeAggFunctions(pParse, &sAggInfo);
3177 if( pHaving ){
3178 sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, 1);
3179 }
3180 rc = selectInnerLoop(pParse, p, p->pEList, 0, 0, pOrderBy,
3181 distinct, eDest, iParm,
3182 addrOutputRow+1, addrSetAbort, aff);
3183 if( rc ){
3184 goto select_end;
3185 }
3186 sqlite3VdbeAddOp(v, OP_Return, 0, 0);
3187 VdbeComment((v, "# end groupby result generator"));
3188
3189 /* Generate a subroutine that will reset the group-by accumulator
3190 */
3191 addrReset = sqlite3VdbeCurrentAddr(v);
3192 resetAccumulator(pParse, &sAggInfo);
3193 sqlite3VdbeAddOp(v, OP_Return, 0, 0);
3194
3195 /* Begin a loop that will extract all source rows in GROUP BY order.
3196 ** This might involve two separate loops with an OP_Sort in between, or
3197 ** it might be a single loop that uses an index to extract information
3198 ** in the right order to begin with.
3199 */
3200 sqlite3VdbeResolveLabel(v, addrInitializeLoop);
3201 sqlite3VdbeAddOp(v, OP_Gosub, 0, addrReset);
3202 pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pGroupBy);
3203 if( pWInfo==0 ) goto select_end;
3204 if( pGroupBy==0 ){
3205 /* The optimizer is able to deliver rows in group by order so
3206 ** we do not have to sort. The OP_OpenEphemeral table will be
3207 ** cancelled later because we still need to use the pKeyInfo
3208 */
3209 pGroupBy = p->pGroupBy;
3210 groupBySort = 0;
3211 }else{
3212 /* Rows are coming out in undetermined order. We have to push
3213 ** each row into a sorting index, terminate the first loop,
3214 ** then loop over the sorting index in order to get the output
3215 ** in sorted order
3216 */
3217 groupBySort = 1;
3218 sqlite3ExprCodeExprList(pParse, pGroupBy);
3219 sqlite3VdbeAddOp(v, OP_Sequence, sAggInfo.sortingIdx, 0);
3220 j = pGroupBy->nExpr+1;
3221 for(i=0; i<sAggInfo.nColumn; i++){
3222 struct AggInfo_col *pCol = &sAggInfo.aCol[i];
3223 if( pCol->iSorterColumn<j ) continue;
3224 sqlite3ExprCodeGetColumn(v, pCol->pTab, pCol->iColumn, pCol->iTable);
3225 j++;
3226 }
3227 sqlite3VdbeAddOp(v, OP_MakeRecord, j, 0);
3228 sqlite3VdbeAddOp(v, OP_IdxInsert, sAggInfo.sortingIdx, 0);
3229 sqlite3WhereEnd(pWInfo);
3230 sqlite3VdbeAddOp(v, OP_Sort, sAggInfo.sortingIdx, addrEnd);
3231 VdbeComment((v, "# GROUP BY sort"));
3232 sAggInfo.useSortingIdx = 1;
3233 }
3234
3235 /* Evaluate the current GROUP BY terms and store in b0, b1, b2...
3236 ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
3237 ** Then compare the current GROUP BY terms against the GROUP BY terms
3238 ** from the previous row currently stored in a0, a1, a2...
3239 */
3240 addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
3241 for(j=0; j<pGroupBy->nExpr; j++){
3242 if( groupBySort ){
3243 sqlite3VdbeAddOp(v, OP_Column, sAggInfo.sortingIdx, j);
3244 }else{
3245 sAggInfo.directMode = 1;
3246 sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr);
3247 }
3248 sqlite3VdbeAddOp(v, OP_MemStore, iBMem+j, j<pGroupBy->nExpr-1);
3249 }
3250 for(j=pGroupBy->nExpr-1; j>=0; j--){
3251 if( j<pGroupBy->nExpr-1 ){
3252 sqlite3VdbeAddOp(v, OP_MemLoad, iBMem+j, 0);
3253 }
3254 sqlite3VdbeAddOp(v, OP_MemLoad, iAMem+j, 0);
3255 if( j==0 ){
3256 sqlite3VdbeAddOp(v, OP_Eq, 0x200, addrProcessRow);
3257 }else{
3258 sqlite3VdbeAddOp(v, OP_Ne, 0x200, addrGroupByChange);
3259 }
3260 sqlite3VdbeChangeP3(v, -1, (void*)pKeyInfo->aColl[j], P3_COLLSEQ);
3261 }
3262
3263 /* Generate code that runs whenever the GROUP BY changes.
3264 ** Change in the GROUP BY are detected by the previous code
3265 ** block. If there were no changes, this block is skipped.
3266 **
3267 ** This code copies current group by terms in b0,b1,b2,...
3268 ** over to a0,a1,a2. It then calls the output subroutine
3269 ** and resets the aggregate accumulator registers in preparation
3270 ** for the next GROUP BY batch.
3271 */
3272 sqlite3VdbeResolveLabel(v, addrGroupByChange);
3273 for(j=0; j<pGroupBy->nExpr; j++){
3274 sqlite3VdbeAddOp(v, OP_MemMove, iAMem+j, iBMem+j);
3275 }
3276 sqlite3VdbeAddOp(v, OP_Gosub, 0, addrOutputRow);
3277 VdbeComment((v, "# output one row"));
3278 sqlite3VdbeAddOp(v, OP_IfMemPos, iAbortFlag, addrEnd);
3279 VdbeComment((v, "# check abort flag"));
3280 sqlite3VdbeAddOp(v, OP_Gosub, 0, addrReset);
3281 VdbeComment((v, "# reset accumulator"));
3282
3283 /* Update the aggregate accumulators based on the content of
3284 ** the current row
3285 */
3286 sqlite3VdbeResolveLabel(v, addrProcessRow);
3287 updateAccumulator(pParse, &sAggInfo);
3288 sqlite3VdbeAddOp(v, OP_MemInt, 1, iUseFlag);
3289 VdbeComment((v, "# indicate data in accumulator"));
3290
3291 /* End of the loop
3292 */
3293 if( groupBySort ){
3294 sqlite3VdbeAddOp(v, OP_Next, sAggInfo.sortingIdx, addrTopOfLoop);
3295 }else{
3296 sqlite3WhereEnd(pWInfo);
3297 sqlite3VdbeChangeToNoop(v, addrSortingIdx, 1);
3298 }
3299
3300 /* Output the final row of result
3301 */
3302 sqlite3VdbeAddOp(v, OP_Gosub, 0, addrOutputRow);
3303 VdbeComment((v, "# output final row"));
3304
3305 } /* endif pGroupBy */
3306 else {
3307 /* This case runs if the aggregate has no GROUP BY clause. The
3308 ** processing is much simpler since there is only a single row
3309 ** of output.
3310 */
3311 resetAccumulator(pParse, &sAggInfo);
3312 pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0);
3313 if( pWInfo==0 ) goto select_end;
3314 updateAccumulator(pParse, &sAggInfo);
3315 sqlite3WhereEnd(pWInfo);
3316 finalizeAggFunctions(pParse, &sAggInfo);
3317 pOrderBy = 0;
3318 if( pHaving ){
3319 sqlite3ExprIfFalse(pParse, pHaving, addrEnd, 1);
3320 }
3321 selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, -1,
3322 eDest, iParm, addrEnd, addrEnd, aff);
3323 }
3324 sqlite3VdbeResolveLabel(v, addrEnd);
3325
3326 } /* endif aggregate query */
3327
3328 /* If there is an ORDER BY clause, then we need to sort the results
3329 ** and send them to the callback one by one.
3330 */
3331 if( pOrderBy ){
3332 generateSortTail(pParse, p, v, pEList->nExpr, eDest, iParm);
3333 }
3334
3335#ifndef SQLITE_OMIT_SUBQUERY
3336 /* If this was a subquery, we have now converted the subquery into a
3337 ** temporary table. So set the SrcList_item.isPopulated flag to prevent
3338 ** this subquery from being evaluated again and to force the use of
3339 ** the temporary table.
3340 */
3341 if( pParent ){
3342 assert( pParent->pSrc->nSrc>parentTab );
3343 assert( pParent->pSrc->a[parentTab].pSelect==p );
3344 pParent->pSrc->a[parentTab].isPopulated = 1;
3345 }
3346#endif
3347
3348 /* Jump here to skip this query
3349 */
3350 sqlite3VdbeResolveLabel(v, iEnd);
3351
3352 /* The SELECT was successfully coded. Set the return code to 0
3353 ** to indicate no errors.
3354 */
3355 rc = 0;
3356
3357 /* Control jumps to here if an error is encountered above, or upon
3358 ** successful coding of the SELECT.
3359 */
3360select_end:
3361
3362 /* Identify column names if we will be using them in a callback. This
3363 ** step is skipped if the output is going to some other destination.
3364 */
3365 if( rc==SQLITE_OK && eDest==SRT_Callback ){
3366 generateColumnNames(pParse, pTabList, pEList);
3367 }
3368
3369 sqliteFree(sAggInfo.aCol);
3370 sqliteFree(sAggInfo.aFunc);
3371 return rc;
3372}
3373
3374#if defined(SQLITE_DEBUG)
3375/*
3376*******************************************************************************
3377** The following code is used for testing and debugging only. The code
3378** that follows does not appear in normal builds.
3379**
3380** These routines are used to print out the content of all or part of a
3381** parse structures such as Select or Expr. Such printouts are useful
3382** for helping to understand what is happening inside the code generator
3383** during the execution of complex SELECT statements.
3384**
3385** These routine are not called anywhere from within the normal
3386** code base. Then are intended to be called from within the debugger
3387** or from temporary "printf" statements inserted for debugging.
3388*/
3389void sqlite3PrintExpr(Expr *p){
3390 if( p->token.z && p->token.n>0 ){
3391 sqlite3DebugPrintf("(%.*s", p->token.n, p->token.z);
3392 }else{
3393 sqlite3DebugPrintf("(%d", p->op);
3394 }
3395 if( p->pLeft ){
3396 sqlite3DebugPrintf(" ");
3397 sqlite3PrintExpr(p->pLeft);
3398 }
3399 if( p->pRight ){
3400 sqlite3DebugPrintf(" ");
3401 sqlite3PrintExpr(p->pRight);
3402 }
3403 sqlite3DebugPrintf(")");
3404}
3405void sqlite3PrintExprList(ExprList *pList){
3406 int i;
3407 for(i=0; i<pList->nExpr; i++){
3408 sqlite3PrintExpr(pList->a[i].pExpr);
3409 if( i<pList->nExpr-1 ){
3410 sqlite3DebugPrintf(", ");
3411 }
3412 }
3413}
3414void sqlite3PrintSelect(Select *p, int indent){
3415 sqlite3DebugPrintf("%*sSELECT(%p) ", indent, "", p);
3416 sqlite3PrintExprList(p->pEList);
3417 sqlite3DebugPrintf("\n");
3418 if( p->pSrc ){
3419 char *zPrefix;
3420 int i;
3421 zPrefix = "FROM";
3422 for(i=0; i<p->pSrc->nSrc; i++){
3423 struct SrcList_item *pItem = &p->pSrc->a[i];
3424 sqlite3DebugPrintf("%*s ", indent+6, zPrefix);
3425 zPrefix = "";
3426 if( pItem->pSelect ){
3427 sqlite3DebugPrintf("(\n");
3428 sqlite3PrintSelect(pItem->pSelect, indent+10);
3429 sqlite3DebugPrintf("%*s)", indent+8, "");
3430 }else if( pItem->zName ){
3431 sqlite3DebugPrintf("%s", pItem->zName);
3432 }
3433 if( pItem->pTab ){
3434 sqlite3DebugPrintf("(table: %s)", pItem->pTab->zName);
3435 }
3436 if( pItem->zAlias ){
3437 sqlite3DebugPrintf(" AS %s", pItem->zAlias);
3438 }
3439 if( i<p->pSrc->nSrc-1 ){
3440 sqlite3DebugPrintf(",");
3441 }
3442 sqlite3DebugPrintf("\n");
3443 }
3444 }
3445 if( p->pWhere ){
3446 sqlite3DebugPrintf("%*s WHERE ", indent, "");
3447 sqlite3PrintExpr(p->pWhere);
3448 sqlite3DebugPrintf("\n");
3449 }
3450 if( p->pGroupBy ){
3451 sqlite3DebugPrintf("%*s GROUP BY ", indent, "");
3452 sqlite3PrintExprList(p->pGroupBy);
3453 sqlite3DebugPrintf("\n");
3454 }
3455 if( p->pHaving ){
3456 sqlite3DebugPrintf("%*s HAVING ", indent, "");
3457 sqlite3PrintExpr(p->pHaving);
3458 sqlite3DebugPrintf("\n");
3459 }
3460 if( p->pOrderBy ){
3461 sqlite3DebugPrintf("%*s ORDER BY ", indent, "");
3462 sqlite3PrintExprList(p->pOrderBy);
3463 sqlite3DebugPrintf("\n");
3464 }
3465}
3466/* End of the structure debug printing code
3467*****************************************************************************/
3468#endif /* defined(SQLITE_TEST) || defined(SQLITE_DEBUG) */

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