4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
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.
11 *************************************************************************
13 ** This file contains routines used for walking the parser tree and
14 ** resolve all identifiers by associating them with a particular
17 #include "sqliteInt.h"
22 ** Turn the pExpr expression into an alias for the iCol-th column of the
23 ** result set in pEList.
25 ** If the result set column is a simple column reference, then this routine
26 ** makes an exact copy. But for any other kind of expression, this
27 ** routine make a copy of the result set column as the argument to the
28 ** TK_AS operator. The TK_AS operator causes the expression to be
29 ** evaluated just once and then reused for each alias.
31 ** The reason for suppressing the TK_AS term when the expression is a simple
32 ** column reference is so that the column reference will be recognized as
33 ** usable by indices within the WHERE clause processing logic.
35 ** Hack: The TK_AS operator is inhibited if zType[0]=='G'. This means
36 ** that in a GROUP BY clause, the expression is evaluated twice. Hence:
38 ** SELECT random()%5 AS x, count(*) FROM tab GROUP BY x
42 ** SELECT random()%5 AS x, count(*) FROM tab GROUP BY random()%5
44 ** The result of random()%5 in the GROUP BY clause is probably different
45 ** from the result in the result-set. We might fix this someday. Or
46 ** then again, we might not...
48 static void resolveAlias(
49 Parse *pParse, /* Parsing context */
50 ExprList *pEList, /* A result set */
51 int iCol, /* A column in the result set. 0..pEList->nExpr-1 */
52 Expr *pExpr, /* Transform this into an alias to the result set */
53 const char *zType /* "GROUP" or "ORDER" or "" */
55 Expr *pOrig; /* The iCol-th column of the result set */
56 Expr *pDup; /* Copy of pOrig */
57 sqlite3 *db; /* The database connection */
59 assert( iCol>=0 && iCol<pEList->nExpr );
60 pOrig = pEList->a[iCol].pExpr;
62 assert( pOrig->flags & EP_Resolved );
64 if( pOrig->op!=TK_COLUMN && zType[0]!='G' ){
65 pDup = sqlite3ExprDup(db, pOrig, 0);
66 pDup = sqlite3PExpr(pParse, TK_AS, pDup, 0, 0);
68 if( pEList->a[iCol].iAlias==0 ){
69 pEList->a[iCol].iAlias = (u16)(++pParse->nAlias);
71 pDup->iTable = pEList->a[iCol].iAlias;
72 }else if( ExprHasProperty(pOrig, EP_IntValue) || pOrig->u.zToken==0 ){
73 pDup = sqlite3ExprDup(db, pOrig, 0);
76 char *zToken = pOrig->u.zToken;
79 pDup = sqlite3ExprDup(db, pOrig, 0);
80 pOrig->u.zToken = zToken;
82 assert( (pDup->flags & (EP_Reduced|EP_TokenOnly))==0 );
83 pDup->flags2 |= EP2_MallocedToken;
84 pDup->u.zToken = sqlite3DbStrDup(db, zToken);
86 if( pExpr->flags & EP_ExpCollate ){
87 pDup->pColl = pExpr->pColl;
88 pDup->flags |= EP_ExpCollate;
91 /* Before calling sqlite3ExprDelete(), set the EP_Static flag. This
92 ** prevents ExprDelete() from deleting the Expr structure itself,
93 ** allowing it to be repopulated by the memcpy() on the following line.
95 ExprSetProperty(pExpr, EP_Static);
96 sqlite3ExprDelete(db, pExpr);
97 memcpy(pExpr, pDup, sizeof(*pExpr));
98 sqlite3DbFree(db, pDup);
102 ** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
103 ** that name in the set of source tables in pSrcList and make the pExpr
104 ** expression node refer back to that source column. The following changes
105 ** are made to pExpr:
107 ** pExpr->iDb Set the index in db->aDb[] of the database X
108 ** (even if X is implied).
109 ** pExpr->iTable Set to the cursor number for the table obtained
111 ** pExpr->pTab Points to the Table structure of X.Y (even if
112 ** X and/or Y are implied.)
113 ** pExpr->iColumn Set to the column number within the table.
114 ** pExpr->op Set to TK_COLUMN.
115 ** pExpr->pLeft Any expression this points to is deleted
116 ** pExpr->pRight Any expression this points to is deleted.
118 ** The zDb variable is the name of the database (the "X"). This value may be
119 ** NULL meaning that name is of the form Y.Z or Z. Any available database
120 ** can be used. The zTable variable is the name of the table (the "Y"). This
121 ** value can be NULL if zDb is also NULL. If zTable is NULL it
122 ** means that the form of the name is Z and that columns from any table
125 ** If the name cannot be resolved unambiguously, leave an error message
126 ** in pParse and return WRC_Abort. Return WRC_Prune on success.
128 static int lookupName(
129 Parse *pParse, /* The parsing context */
130 const char *zDb, /* Name of the database containing table, or NULL */
131 const char *zTab, /* Name of table containing column, or NULL */
132 const char *zCol, /* Name of the column. */
133 NameContext *pNC, /* The name context used to resolve the name */
134 Expr *pExpr /* Make this EXPR node point to the selected column */
136 int i, j; /* Loop counters */
137 int cnt = 0; /* Number of matching column names */
138 int cntTab = 0; /* Number of matching table names */
139 sqlite3 *db = pParse->db; /* The database connection */
140 struct SrcList_item *pItem; /* Use for looping over pSrcList items */
141 struct SrcList_item *pMatch = 0; /* The matching pSrcList item */
142 NameContext *pTopNC = pNC; /* First namecontext in the list */
143 Schema *pSchema = 0; /* Schema of the expression */
146 assert( pNC ); /* the name context cannot be NULL. */
147 assert( zCol ); /* The Z in X.Y.Z cannot be NULL */
148 assert( ~ExprHasAnyProperty(pExpr, EP_TokenOnly|EP_Reduced) );
150 /* Initialize the node to no-match */
153 ExprSetIrreducible(pExpr);
155 /* Start at the inner-most context and move outward until a match is found */
156 while( pNC && cnt==0 ){
158 SrcList *pSrcList = pNC->pSrcList;
161 for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){
167 assert( pTab!=0 && pTab->zName!=0 );
168 iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
169 assert( pTab->nCol>0 );
172 char *zTabName = pItem->zAlias;
173 if( sqlite3StrICmp(zTabName, zTab)!=0 ) continue;
175 char *zTabName = pTab->zName;
176 if( NEVER(zTabName==0) || sqlite3StrICmp(zTabName, zTab)!=0 ){
179 if( zDb!=0 && sqlite3StrICmp(db->aDb[iDb].zName, zDb)!=0 ){
185 pExpr->iTable = pItem->iCursor;
187 pSchema = pTab->pSchema;
190 for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
191 if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
194 pExpr->iTable = pItem->iCursor;
197 pSchema = pTab->pSchema;
198 /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
199 pExpr->iColumn = j==pTab->iPKey ? -1 : (i16)j;
200 if( i<pSrcList->nSrc-1 ){
201 if( pItem[1].jointype & JT_NATURAL ){
202 /* If this match occurred in the left table of a natural join,
203 ** then skip the right table to avoid a duplicate match */
206 }else if( (pUsing = pItem[1].pUsing)!=0 ){
207 /* If this match occurs on a column that is in the USING clause
208 ** of a join, skip the search of the right table of the join
209 ** to avoid a duplicate match there. */
211 for(k=0; k<pUsing->nId; k++){
212 if( sqlite3StrICmp(pUsing->a[k].zName, zCol)==0 ){
226 #ifndef SQLITE_OMIT_TRIGGER
227 /* If we have not already resolved the name, then maybe
228 ** it is a new.* or old.* trigger argument reference
230 if( zDb==0 && zTab!=0 && cnt==0 && pParse->pTriggerTab!=0 ){
231 int op = pParse->eTriggerOp;
233 assert( op==TK_DELETE || op==TK_UPDATE || op==TK_INSERT );
234 if( op!=TK_DELETE && sqlite3StrICmp("new",zTab) == 0 ){
236 pTab = pParse->pTriggerTab;
237 }else if( op!=TK_INSERT && sqlite3StrICmp("old",zTab)==0 ){
239 pTab = pParse->pTriggerTab;
244 pSchema = pTab->pSchema;
246 for(iCol=0; iCol<pTab->nCol; iCol++){
247 Column *pCol = &pTab->aCol[iCol];
248 if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
249 if( iCol==pTab->iPKey ){
255 if( iCol>=pTab->nCol && sqlite3IsRowid(zCol) ){
256 iCol = -1; /* IMP: R-44911-55124 */
258 if( iCol<pTab->nCol ){
261 pExpr->affinity = SQLITE_AFF_INTEGER;
262 }else if( pExpr->iTable==0 ){
263 testcase( iCol==31 );
264 testcase( iCol==32 );
265 pParse->oldmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
267 testcase( iCol==31 );
268 testcase( iCol==32 );
269 pParse->newmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
271 pExpr->iColumn = (i16)iCol;
277 #endif /* !defined(SQLITE_OMIT_TRIGGER) */
280 ** Perhaps the name is a reference to the ROWID
282 if( cnt==0 && cntTab==1 && sqlite3IsRowid(zCol) ){
284 pExpr->iColumn = -1; /* IMP: R-44911-55124 */
285 pExpr->affinity = SQLITE_AFF_INTEGER;
289 ** If the input is of the form Z (not Y.Z or X.Y.Z) then the name Z
290 ** might refer to an result-set alias. This happens, for example, when
291 ** we are resolving names in the WHERE clause of the following command:
293 ** SELECT a+b AS x FROM table WHERE x<10;
295 ** In cases like this, replace pExpr with a copy of the expression that
296 ** forms the result set entry ("a+b" in the example) and return immediately.
297 ** Note that the expression in the result set should have already been
298 ** resolved by the time the WHERE clause is resolved.
300 if( cnt==0 && (pEList = pNC->pEList)!=0 && zTab==0 ){
301 for(j=0; j<pEList->nExpr; j++){
302 char *zAs = pEList->a[j].zName;
303 if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){
305 assert( pExpr->pLeft==0 && pExpr->pRight==0 );
306 assert( pExpr->x.pList==0 );
307 assert( pExpr->x.pSelect==0 );
308 pOrig = pEList->a[j].pExpr;
309 if( !pNC->allowAgg && ExprHasProperty(pOrig, EP_Agg) ){
310 sqlite3ErrorMsg(pParse, "misuse of aliased aggregate %s", zAs);
313 resolveAlias(pParse, pEList, j, pExpr, "");
316 assert( zTab==0 && zDb==0 );
322 /* Advance to the next name context. The loop will exit when either
323 ** we have a match (cnt>0) or when we run out of name contexts.
331 ** If X and Y are NULL (in other words if only the column name Z is
332 ** supplied) and the value of Z is enclosed in double-quotes, then
333 ** Z is a string literal if it doesn't match any column names. In that
334 ** case, we need to return right away and not make any changes to
337 ** Because no reference was made to outer contexts, the pNC->nRef
338 ** fields are not changed in any context.
340 if( cnt==0 && zTab==0 && ExprHasProperty(pExpr,EP_DblQuoted) ){
341 pExpr->op = TK_STRING;
347 ** cnt==0 means there was not match. cnt>1 means there were two or
348 ** more matches. Either way, we have an error.
352 zErr = cnt==0 ? "no such column" : "ambiguous column name";
354 sqlite3ErrorMsg(pParse, "%s: %s.%s.%s", zErr, zDb, zTab, zCol);
356 sqlite3ErrorMsg(pParse, "%s: %s.%s", zErr, zTab, zCol);
358 sqlite3ErrorMsg(pParse, "%s: %s", zErr, zCol);
360 pParse->checkSchema = 1;
364 /* If a column from a table in pSrcList is referenced, then record
365 ** this fact in the pSrcList.a[].colUsed bitmask. Column 0 causes
366 ** bit 0 to be set. Column 1 sets bit 1. And so forth. If the
367 ** column number is greater than the number of bits in the bitmask
368 ** then set the high-order bit of the bitmask.
370 if( pExpr->iColumn>=0 && pMatch!=0 ){
371 int n = pExpr->iColumn;
372 testcase( n==BMS-1 );
376 assert( pMatch->iCursor==pExpr->iTable );
377 pMatch->colUsed |= ((Bitmask)1)<<n;
380 /* Clean up and return
382 sqlite3ExprDelete(db, pExpr->pLeft);
384 sqlite3ExprDelete(db, pExpr->pRight);
386 pExpr->op = (isTrigger ? TK_TRIGGER : TK_COLUMN);
390 sqlite3AuthRead(pParse, pExpr, pSchema, pNC->pSrcList);
391 /* Increment the nRef value on all name contexts from TopNC up to
392 ** the point where the name matched. */
396 if( pTopNC==pNC ) break;
397 pTopNC = pTopNC->pNext;
406 ** Allocate and return a pointer to an expression to load the column iCol
407 ** from datasource iSrc in SrcList pSrc.
409 Expr *sqlite3CreateColumnExpr(sqlite3 *db, SrcList *pSrc, int iSrc, int iCol){
410 Expr *p = sqlite3ExprAlloc(db, TK_COLUMN, 0, 0);
412 struct SrcList_item *pItem = &pSrc->a[iSrc];
413 p->pTab = pItem->pTab;
414 p->iTable = pItem->iCursor;
415 if( p->pTab->iPKey==iCol ){
418 p->iColumn = (ynVar)iCol;
419 testcase( iCol==BMS );
420 testcase( iCol==BMS-1 );
421 pItem->colUsed |= ((Bitmask)1)<<(iCol>=BMS ? BMS-1 : iCol);
423 ExprSetProperty(p, EP_Resolved);
429 ** This routine is callback for sqlite3WalkExpr().
431 ** Resolve symbolic names into TK_COLUMN operators for the current
432 ** node in the expression tree. Return 0 to continue the search down
433 ** the tree or 2 to abort the tree walk.
435 ** This routine also does error checking and name resolution for
436 ** function names. The operator for aggregate functions is changed
437 ** to TK_AGG_FUNCTION.
439 static int resolveExprStep(Walker *pWalker, Expr *pExpr){
443 pNC = pWalker->u.pNC;
445 pParse = pNC->pParse;
446 assert( pParse==pWalker->pParse );
448 if( ExprHasAnyProperty(pExpr, EP_Resolved) ) return WRC_Prune;
449 ExprSetProperty(pExpr, EP_Resolved);
451 if( pNC->pSrcList && pNC->pSrcList->nAlloc>0 ){
452 SrcList *pSrcList = pNC->pSrcList;
454 for(i=0; i<pNC->pSrcList->nSrc; i++){
455 assert( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab);
461 #if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
462 /* The special operator TK_ROW means use the rowid for the first
463 ** column in the FROM clause. This is used by the LIMIT and ORDER BY
464 ** clause processing on UPDATE and DELETE statements.
467 SrcList *pSrcList = pNC->pSrcList;
468 struct SrcList_item *pItem;
469 assert( pSrcList && pSrcList->nSrc==1 );
471 pExpr->op = TK_COLUMN;
472 pExpr->pTab = pItem->pTab;
473 pExpr->iTable = pItem->iCursor;
475 pExpr->affinity = SQLITE_AFF_INTEGER;
478 #endif /* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY) */
480 /* A lone identifier is the name of a column.
483 return lookupName(pParse, 0, 0, pExpr->u.zToken, pNC, pExpr);
486 /* A table name and column name: ID.ID
487 ** Or a database, table and column: ID.ID.ID
495 /* if( pSrcList==0 ) break; */
496 pRight = pExpr->pRight;
497 if( pRight->op==TK_ID ){
499 zTable = pExpr->pLeft->u.zToken;
500 zColumn = pRight->u.zToken;
502 assert( pRight->op==TK_DOT );
503 zDb = pExpr->pLeft->u.zToken;
504 zTable = pRight->pLeft->u.zToken;
505 zColumn = pRight->pRight->u.zToken;
507 return lookupName(pParse, zDb, zTable, zColumn, pNC, pExpr);
510 /* Resolve function names
514 ExprList *pList = pExpr->x.pList; /* The argument list */
515 int n = pList ? pList->nExpr : 0; /* Number of arguments */
516 int no_such_func = 0; /* True if no such function exists */
517 int wrong_num_args = 0; /* True if wrong number of arguments */
518 int is_agg = 0; /* True if is an aggregate function */
519 int auth; /* Authorization to use the function */
520 int nId; /* Number of characters in function name */
521 const char *zId; /* The function name. */
522 FuncDef *pDef; /* Information about the function */
523 u8 enc = ENC(pParse->db); /* The database encoding */
525 testcase( pExpr->op==TK_CONST_FUNC );
526 assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
527 zId = pExpr->u.zToken;
528 nId = sqlite3Strlen30(zId);
529 pDef = sqlite3FindFunction(pParse->db, zId, nId, n, enc, 0);
531 pDef = sqlite3FindFunction(pParse->db, zId, nId, -1, enc, 0);
538 is_agg = pDef->xFunc==0;
540 #ifndef SQLITE_OMIT_AUTHORIZATION
542 auth = sqlite3AuthCheck(pParse, SQLITE_FUNCTION, 0, pDef->zName, 0);
543 if( auth!=SQLITE_OK ){
544 if( auth==SQLITE_DENY ){
545 sqlite3ErrorMsg(pParse, "not authorized to use function: %s",
554 if( is_agg && !pNC->allowAgg ){
555 sqlite3ErrorMsg(pParse, "misuse of aggregate function %.*s()", nId,zId);
558 }else if( no_such_func ){
559 sqlite3ErrorMsg(pParse, "no such function: %.*s", nId, zId);
561 }else if( wrong_num_args ){
562 sqlite3ErrorMsg(pParse,"wrong number of arguments to function %.*s()",
567 pExpr->op = TK_AGG_FUNCTION;
570 if( is_agg ) pNC->allowAgg = 0;
571 sqlite3WalkExprList(pWalker, pList);
572 if( is_agg ) pNC->allowAgg = 1;
573 /* FIX ME: Compute pExpr->affinity based on the expected return
574 ** type of the function
578 #ifndef SQLITE_OMIT_SUBQUERY
580 case TK_EXISTS: testcase( pExpr->op==TK_EXISTS );
583 testcase( pExpr->op==TK_IN );
584 if( ExprHasProperty(pExpr, EP_xIsSelect) ){
585 int nRef = pNC->nRef;
586 #ifndef SQLITE_OMIT_CHECK
588 sqlite3ErrorMsg(pParse,"subqueries prohibited in CHECK constraints");
591 sqlite3WalkSelect(pWalker, pExpr->x.pSelect);
592 assert( pNC->nRef>=nRef );
593 if( nRef!=pNC->nRef ){
594 ExprSetProperty(pExpr, EP_VarSelect);
599 #ifndef SQLITE_OMIT_CHECK
602 sqlite3ErrorMsg(pParse,"parameters prohibited in CHECK constraints");
608 return (pParse->nErr || pParse->db->mallocFailed) ? WRC_Abort : WRC_Continue;
612 ** pEList is a list of expressions which are really the result set of the
613 ** a SELECT statement. pE is a term in an ORDER BY or GROUP BY clause.
614 ** This routine checks to see if pE is a simple identifier which corresponds
615 ** to the AS-name of one of the terms of the expression list. If it is,
616 ** this routine return an integer between 1 and N where N is the number of
617 ** elements in pEList, corresponding to the matching entry. If there is
618 ** no match, or if pE is not a simple identifier, then this routine
621 ** pEList has been resolved. pE has not.
623 static int resolveAsName(
624 Parse *pParse, /* Parsing context for error messages */
625 ExprList *pEList, /* List of expressions to scan */
626 Expr *pE /* Expression we are trying to match */
628 int i; /* Loop counter */
630 UNUSED_PARAMETER(pParse);
633 char *zCol = pE->u.zToken;
634 for(i=0; i<pEList->nExpr; i++){
635 char *zAs = pEList->a[i].zName;
636 if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){
645 ** pE is a pointer to an expression which is a single term in the
646 ** ORDER BY of a compound SELECT. The expression has not been
649 ** At the point this routine is called, we already know that the
650 ** ORDER BY term is not an integer index into the result set. That
651 ** case is handled by the calling routine.
653 ** Attempt to match pE against result set columns in the left-most
654 ** SELECT statement. Return the index i of the matching column,
655 ** as an indication to the caller that it should sort by the i-th column.
656 ** The left-most column is 1. In other words, the value returned is the
657 ** same integer value that would be used in the SQL statement to indicate
660 ** If there is no match, return 0. Return -1 if an error occurs.
662 static int resolveOrderByTermToExprList(
663 Parse *pParse, /* Parsing context for error messages */
664 Select *pSelect, /* The SELECT statement with the ORDER BY clause */
665 Expr *pE /* The specific ORDER BY term */
667 int i; /* Loop counter */
668 ExprList *pEList; /* The columns of the result set */
669 NameContext nc; /* Name context for resolving pE */
670 sqlite3 *db; /* Database connection */
671 int rc; /* Return code from subprocedures */
672 u8 savedSuppErr; /* Saved value of db->suppressErr */
674 assert( sqlite3ExprIsInteger(pE, &i)==0 );
675 pEList = pSelect->pEList;
677 /* Resolve all names in the ORDER BY term expression
679 memset(&nc, 0, sizeof(nc));
681 nc.pSrcList = pSelect->pSrc;
686 savedSuppErr = db->suppressErr;
688 rc = sqlite3ResolveExprNames(&nc, pE);
689 db->suppressErr = savedSuppErr;
692 /* Try to match the ORDER BY expression against an expression
693 ** in the result set. Return an 1-based index of the matching
696 for(i=0; i<pEList->nExpr; i++){
697 if( sqlite3ExprCompare(pEList->a[i].pExpr, pE)<2 ){
702 /* If no match, return 0. */
707 ** Generate an ORDER BY or GROUP BY term out-of-range error.
709 static void resolveOutOfRangeError(
710 Parse *pParse, /* The error context into which to write the error */
711 const char *zType, /* "ORDER" or "GROUP" */
712 int i, /* The index (1-based) of the term out of range */
713 int mx /* Largest permissible value of i */
715 sqlite3ErrorMsg(pParse,
716 "%r %s BY term out of range - should be "
717 "between 1 and %d", i, zType, mx);
721 ** Analyze the ORDER BY clause in a compound SELECT statement. Modify
722 ** each term of the ORDER BY clause is a constant integer between 1
723 ** and N where N is the number of columns in the compound SELECT.
725 ** ORDER BY terms that are already an integer between 1 and N are
726 ** unmodified. ORDER BY terms that are integers outside the range of
727 ** 1 through N generate an error. ORDER BY terms that are expressions
728 ** are matched against result set expressions of compound SELECT
729 ** beginning with the left-most SELECT and working toward the right.
730 ** At the first match, the ORDER BY expression is transformed into
731 ** the integer column number.
733 ** Return the number of errors seen.
735 static int resolveCompoundOrderBy(
736 Parse *pParse, /* Parsing context. Leave error messages here */
737 Select *pSelect /* The SELECT statement containing the ORDER BY */
745 pOrderBy = pSelect->pOrderBy;
746 if( pOrderBy==0 ) return 0;
748 #if SQLITE_MAX_COLUMN
749 if( pOrderBy->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
750 sqlite3ErrorMsg(pParse, "too many terms in ORDER BY clause");
754 for(i=0; i<pOrderBy->nExpr; i++){
755 pOrderBy->a[i].done = 0;
758 while( pSelect->pPrior ){
759 pSelect->pPrior->pNext = pSelect;
760 pSelect = pSelect->pPrior;
762 while( pSelect && moreToDo ){
763 struct ExprList_item *pItem;
765 pEList = pSelect->pEList;
767 for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
770 if( pItem->done ) continue;
772 if( sqlite3ExprIsInteger(pE, &iCol) ){
773 if( iCol<=0 || iCol>pEList->nExpr ){
774 resolveOutOfRangeError(pParse, "ORDER", i+1, pEList->nExpr);
778 iCol = resolveAsName(pParse, pEList, pE);
780 pDup = sqlite3ExprDup(db, pE, 0);
781 if( !db->mallocFailed ){
783 iCol = resolveOrderByTermToExprList(pParse, pSelect, pDup);
785 sqlite3ExprDelete(db, pDup);
789 CollSeq *pColl = pE->pColl;
790 int flags = pE->flags & EP_ExpCollate;
791 sqlite3ExprDelete(db, pE);
792 pItem->pExpr = pE = sqlite3Expr(db, TK_INTEGER, 0);
793 if( pE==0 ) return 1;
795 pE->flags |= EP_IntValue | flags;
797 pItem->iCol = (u16)iCol;
803 pSelect = pSelect->pNext;
805 for(i=0; i<pOrderBy->nExpr; i++){
806 if( pOrderBy->a[i].done==0 ){
807 sqlite3ErrorMsg(pParse, "%r ORDER BY term does not match any "
808 "column in the result set", i+1);
816 ** Check every term in the ORDER BY or GROUP BY clause pOrderBy of
817 ** the SELECT statement pSelect. If any term is reference to a
818 ** result set expression (as determined by the ExprList.a.iCol field)
819 ** then convert that term into a copy of the corresponding result set
822 ** If any errors are detected, add an error message to pParse and
823 ** return non-zero. Return zero if no errors are seen.
825 int sqlite3ResolveOrderGroupBy(
826 Parse *pParse, /* Parsing context. Leave error messages here */
827 Select *pSelect, /* The SELECT statement containing the clause */
828 ExprList *pOrderBy, /* The ORDER BY or GROUP BY clause to be processed */
829 const char *zType /* "ORDER" or "GROUP" */
832 sqlite3 *db = pParse->db;
834 struct ExprList_item *pItem;
836 if( pOrderBy==0 || pParse->db->mallocFailed ) return 0;
837 #if SQLITE_MAX_COLUMN
838 if( pOrderBy->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
839 sqlite3ErrorMsg(pParse, "too many terms in %s BY clause", zType);
843 pEList = pSelect->pEList;
844 assert( pEList!=0 ); /* sqlite3SelectNew() guarantees this */
845 for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
847 if( pItem->iCol>pEList->nExpr ){
848 resolveOutOfRangeError(pParse, zType, i+1, pEList->nExpr);
851 resolveAlias(pParse, pEList, pItem->iCol-1, pItem->pExpr, zType);
858 ** pOrderBy is an ORDER BY or GROUP BY clause in SELECT statement pSelect.
859 ** The Name context of the SELECT statement is pNC. zType is either
860 ** "ORDER" or "GROUP" depending on which type of clause pOrderBy is.
862 ** This routine resolves each term of the clause into an expression.
863 ** If the order-by term is an integer I between 1 and N (where N is the
864 ** number of columns in the result set of the SELECT) then the expression
865 ** in the resolution is a copy of the I-th result-set expression. If
866 ** the order-by term is an identify that corresponds to the AS-name of
867 ** a result-set expression, then the term resolves to a copy of the
868 ** result-set expression. Otherwise, the expression is resolved in
869 ** the usual way - using sqlite3ResolveExprNames().
871 ** This routine returns the number of errors. If errors occur, then
872 ** an appropriate error message might be left in pParse. (OOM errors
875 static int resolveOrderGroupBy(
876 NameContext *pNC, /* The name context of the SELECT statement */
877 Select *pSelect, /* The SELECT statement holding pOrderBy */
878 ExprList *pOrderBy, /* An ORDER BY or GROUP BY clause to resolve */
879 const char *zType /* Either "ORDER" or "GROUP", as appropriate */
881 int i; /* Loop counter */
882 int iCol; /* Column number */
883 struct ExprList_item *pItem; /* A term of the ORDER BY clause */
884 Parse *pParse; /* Parsing context */
885 int nResult; /* Number of terms in the result set */
887 if( pOrderBy==0 ) return 0;
888 nResult = pSelect->pEList->nExpr;
889 pParse = pNC->pParse;
890 for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
891 Expr *pE = pItem->pExpr;
892 iCol = resolveAsName(pParse, pSelect->pEList, pE);
894 /* If an AS-name match is found, mark this ORDER BY column as being
895 ** a copy of the iCol-th result-set column. The subsequent call to
896 ** sqlite3ResolveOrderGroupBy() will convert the expression to a
897 ** copy of the iCol-th result-set expression. */
898 pItem->iCol = (u16)iCol;
901 if( sqlite3ExprIsInteger(pE, &iCol) ){
902 /* The ORDER BY term is an integer constant. Again, set the column
903 ** number so that sqlite3ResolveOrderGroupBy() will convert the
904 ** order-by term to a copy of the result-set expression */
906 resolveOutOfRangeError(pParse, zType, i+1, nResult);
909 pItem->iCol = (u16)iCol;
913 /* Otherwise, treat the ORDER BY term as an ordinary expression */
915 if( sqlite3ResolveExprNames(pNC, pE) ){
919 return sqlite3ResolveOrderGroupBy(pParse, pSelect, pOrderBy, zType);
923 ** Resolve names in the SELECT statement p and all of its descendents.
925 static int resolveSelectStep(Walker *pWalker, Select *p){
926 NameContext *pOuterNC; /* Context that contains this SELECT */
927 NameContext sNC; /* Name context of this SELECT */
928 int isCompound; /* True if p is a compound select */
929 int nCompound; /* Number of compound terms processed so far */
930 Parse *pParse; /* Parsing context */
931 ExprList *pEList; /* Result set expression list */
932 int i; /* Loop counter */
933 ExprList *pGroupBy; /* The GROUP BY clause */
934 Select *pLeftmost; /* Left-most of SELECT of a compound */
935 sqlite3 *db; /* Database connection */
939 if( p->selFlags & SF_Resolved ){
942 pOuterNC = pWalker->u.pNC;
943 pParse = pWalker->pParse;
946 /* Normally sqlite3SelectExpand() will be called first and will have
947 ** already expanded this SELECT. However, if this is a subquery within
948 ** an expression, sqlite3ResolveExprNames() will be called without a
949 ** prior call to sqlite3SelectExpand(). When that happens, let
950 ** sqlite3SelectPrep() do all of the processing for this SELECT.
951 ** sqlite3SelectPrep() will invoke both sqlite3SelectExpand() and
952 ** this routine in the correct order.
954 if( (p->selFlags & SF_Expanded)==0 ){
955 sqlite3SelectPrep(pParse, p, pOuterNC);
956 return (pParse->nErr || db->mallocFailed) ? WRC_Abort : WRC_Prune;
959 isCompound = p->pPrior!=0;
963 assert( (p->selFlags & SF_Expanded)!=0 );
964 assert( (p->selFlags & SF_Resolved)==0 );
965 p->selFlags |= SF_Resolved;
967 /* Resolve the expressions in the LIMIT and OFFSET clauses. These
968 ** are not allowed to refer to any names, so pass an empty NameContext.
970 memset(&sNC, 0, sizeof(sNC));
972 if( sqlite3ResolveExprNames(&sNC, p->pLimit) ||
973 sqlite3ResolveExprNames(&sNC, p->pOffset) ){
977 /* Set up the local name-context to pass to sqlite3ResolveExprNames() to
978 ** resolve the result-set expression list.
981 sNC.pSrcList = p->pSrc;
982 sNC.pNext = pOuterNC;
984 /* Resolve names in the result set. */
987 for(i=0; i<pEList->nExpr; i++){
988 Expr *pX = pEList->a[i].pExpr;
989 if( sqlite3ResolveExprNames(&sNC, pX) ){
994 /* Recursively resolve names in all subqueries
996 for(i=0; i<p->pSrc->nSrc; i++){
997 struct SrcList_item *pItem = &p->pSrc->a[i];
998 if( pItem->pSelect ){
999 const char *zSavedContext = pParse->zAuthContext;
1000 if( pItem->zName ) pParse->zAuthContext = pItem->zName;
1001 sqlite3ResolveSelectNames(pParse, pItem->pSelect, pOuterNC);
1002 pParse->zAuthContext = zSavedContext;
1003 if( pParse->nErr || db->mallocFailed ) return WRC_Abort;
1007 /* If there are no aggregate functions in the result-set, and no GROUP BY
1008 ** expression, do not allow aggregates in any of the other expressions.
1010 assert( (p->selFlags & SF_Aggregate)==0 );
1011 pGroupBy = p->pGroupBy;
1012 if( pGroupBy || sNC.hasAgg ){
1013 p->selFlags |= SF_Aggregate;
1018 /* If a HAVING clause is present, then there must be a GROUP BY clause.
1020 if( p->pHaving && !pGroupBy ){
1021 sqlite3ErrorMsg(pParse, "a GROUP BY clause is required before HAVING");
1025 /* Add the expression list to the name-context before parsing the
1026 ** other expressions in the SELECT statement. This is so that
1027 ** expressions in the WHERE clause (etc.) can refer to expressions by
1028 ** aliases in the result set.
1030 ** Minor point: If this is the case, then the expression will be
1031 ** re-evaluated for each reference to it.
1033 sNC.pEList = p->pEList;
1034 if( sqlite3ResolveExprNames(&sNC, p->pWhere) ||
1035 sqlite3ResolveExprNames(&sNC, p->pHaving)
1040 /* The ORDER BY and GROUP BY clauses may not refer to terms in
1046 /* Process the ORDER BY clause for singleton SELECT statements.
1047 ** The ORDER BY clause for compounds SELECT statements is handled
1048 ** below, after all of the result-sets for all of the elements of
1049 ** the compound have been resolved.
1051 if( !isCompound && resolveOrderGroupBy(&sNC, p, p->pOrderBy, "ORDER") ){
1054 if( db->mallocFailed ){
1058 /* Resolve the GROUP BY clause. At the same time, make sure
1059 ** the GROUP BY clause does not contain aggregate functions.
1062 struct ExprList_item *pItem;
1064 if( resolveOrderGroupBy(&sNC, p, pGroupBy, "GROUP") || db->mallocFailed ){
1067 for(i=0, pItem=pGroupBy->a; i<pGroupBy->nExpr; i++, pItem++){
1068 if( ExprHasProperty(pItem->pExpr, EP_Agg) ){
1069 sqlite3ErrorMsg(pParse, "aggregate functions are not allowed in "
1070 "the GROUP BY clause");
1076 /* Advance to the next term of the compound
1082 /* Resolve the ORDER BY on a compound SELECT after all terms of
1083 ** the compound have been resolved.
1085 if( isCompound && resolveCompoundOrderBy(pParse, pLeftmost) ){
1093 ** This routine walks an expression tree and resolves references to
1094 ** table columns and result-set columns. At the same time, do error
1095 ** checking on function usage and set a flag if any aggregate functions
1098 ** To resolve table columns references we look for nodes (or subtrees) of the
1099 ** form X.Y.Z or Y.Z or just Z where
1101 ** X: The name of a database. Ex: "main" or "temp" or
1102 ** the symbolic name assigned to an ATTACH-ed database.
1104 ** Y: The name of a table in a FROM clause. Or in a trigger
1105 ** one of the special names "old" or "new".
1107 ** Z: The name of a column in table Y.
1109 ** The node at the root of the subtree is modified as follows:
1111 ** Expr.op Changed to TK_COLUMN
1112 ** Expr.pTab Points to the Table object for X.Y
1113 ** Expr.iColumn The column index in X.Y. -1 for the rowid.
1114 ** Expr.iTable The VDBE cursor number for X.Y
1117 ** To resolve result-set references, look for expression nodes of the
1118 ** form Z (with no X and Y prefix) where the Z matches the right-hand
1119 ** size of an AS clause in the result-set of a SELECT. The Z expression
1120 ** is replaced by a copy of the left-hand side of the result-set expression.
1121 ** Table-name and function resolution occurs on the substituted expression
1122 ** tree. For example, in:
1124 ** SELECT a+b AS x, c+d AS y FROM t1 ORDER BY x;
1126 ** The "x" term of the order by is replaced by "a+b" to render:
1128 ** SELECT a+b AS x, c+d AS y FROM t1 ORDER BY a+b;
1130 ** Function calls are checked to make sure that the function is
1131 ** defined and that the correct number of arguments are specified.
1132 ** If the function is an aggregate function, then the pNC->hasAgg is
1133 ** set and the opcode is changed from TK_FUNCTION to TK_AGG_FUNCTION.
1134 ** If an expression contains aggregate functions then the EP_Agg
1135 ** property on the expression is set.
1137 ** An error message is left in pParse if anything is amiss. The number
1138 ** if errors is returned.
1140 int sqlite3ResolveExprNames(
1141 NameContext *pNC, /* Namespace to resolve expressions in. */
1142 Expr *pExpr /* The expression to be analyzed. */
1147 if( pExpr==0 ) return 0;
1148 #if SQLITE_MAX_EXPR_DEPTH>0
1150 Parse *pParse = pNC->pParse;
1151 if( sqlite3ExprCheckHeight(pParse, pExpr->nHeight+pNC->pParse->nHeight) ){
1154 pParse->nHeight += pExpr->nHeight;
1157 savedHasAgg = pNC->hasAgg;
1159 w.xExprCallback = resolveExprStep;
1160 w.xSelectCallback = resolveSelectStep;
1161 w.pParse = pNC->pParse;
1163 sqlite3WalkExpr(&w, pExpr);
1164 #if SQLITE_MAX_EXPR_DEPTH>0
1165 pNC->pParse->nHeight -= pExpr->nHeight;
1167 if( pNC->nErr>0 || w.pParse->nErr>0 ){
1168 ExprSetProperty(pExpr, EP_Error);
1171 ExprSetProperty(pExpr, EP_Agg);
1172 }else if( savedHasAgg ){
1175 return ExprHasProperty(pExpr, EP_Error);
1180 ** Resolve all names in all expressions of a SELECT and in all
1181 ** decendents of the SELECT, including compounds off of p->pPrior,
1182 ** subqueries in expressions, and subqueries used as FROM clause
1185 ** See sqlite3ResolveExprNames() for a description of the kinds of
1186 ** transformations that occur.
1188 ** All SELECT statements should have been expanded using
1189 ** sqlite3SelectExpand() prior to invoking this routine.
1191 void sqlite3ResolveSelectNames(
1192 Parse *pParse, /* The parser context */
1193 Select *p, /* The SELECT statement being coded. */
1194 NameContext *pOuterNC /* Name context for parent SELECT statement */
1199 w.xExprCallback = resolveExprStep;
1200 w.xSelectCallback = resolveSelectStep;
1203 sqlite3WalkSelect(&w, p);