Index: src/expr.c ================================================================== --- src/expr.c +++ src/expr.c @@ -3796,10 +3796,13 @@ ** Do a deep comparison of two expression trees. Return 0 if the two ** expressions are completely identical. Return 1 if they differ only ** by a COLLATE operator at the top level. Return 2 if there are differences ** other than the top-level COLLATE operator. ** +** If any subelement of pB has Expr.iTable==(-1) then it is allowed +** to compare equal to an equivalent element in pA with Expr.iTable==iTab. +** ** Sometimes this routine will return 2 even if the two expressions ** really are equivalent. If we cannot prove that the expressions are ** identical, we return 2 just to be safe. So if this routine ** returns 2, then you do not really know for certain if the two ** expressions are the same. But if you get a 0 or 1 return, then you @@ -3806,11 +3809,11 @@ ** can be sure the expressions are the same. In the places where ** this routine is used, it does not hurt to get an extra 2 - that ** just might result in some slightly slower code. But returning ** an incorrect 0 or 1 could lead to a malfunction. */ -int sqlite3ExprCompare(Expr *pA, Expr *pB){ +int sqlite3ExprCompare(Expr *pA, Expr *pB, int iTab){ if( pA==0||pB==0 ){ return pB==pA ? 0 : 2; } assert( !ExprHasAnyProperty(pA, EP_TokenOnly|EP_Reduced) ); assert( !ExprHasAnyProperty(pB, EP_TokenOnly|EP_Reduced) ); @@ -3817,22 +3820,23 @@ if( ExprHasProperty(pA, EP_xIsSelect) || ExprHasProperty(pB, EP_xIsSelect) ){ return 2; } if( (pA->flags & EP_Distinct)!=(pB->flags & EP_Distinct) ) return 2; if( pA->op!=pB->op ){ - if( pA->op==TK_COLLATE && sqlite3ExprCompare(pA->pLeft, pB)<2 ){ + if( pA->op==TK_COLLATE && sqlite3ExprCompare(pA->pLeft, pB, iTab)<2 ){ return 1; } - if( pB->op==TK_COLLATE && sqlite3ExprCompare(pA, pB->pLeft)<2 ){ + if( pB->op==TK_COLLATE && sqlite3ExprCompare(pA, pB->pLeft, iTab)<2 ){ return 1; } return 2; } - if( sqlite3ExprCompare(pA->pLeft, pB->pLeft) ) return 2; - if( sqlite3ExprCompare(pA->pRight, pB->pRight) ) return 2; - if( sqlite3ExprListCompare(pA->x.pList, pB->x.pList) ) return 2; - if( pA->iTable!=pB->iTable || pA->iColumn!=pB->iColumn ) return 2; + if( sqlite3ExprCompare(pA->pLeft, pB->pLeft, iTab) ) return 2; + if( sqlite3ExprCompare(pA->pRight, pB->pRight, iTab) ) return 2; + if( sqlite3ExprListCompare(pA->x.pList, pB->x.pList, iTab) ) return 2; + if( pA->iColumn!=pB->iColumn ) return 2; + if( pA->iTable!=pB->iTable && (pA->iTable!=iTab || pB->iTable>=0) ) return 2; if( ExprHasProperty(pA, EP_IntValue) ){ if( !ExprHasProperty(pB, EP_IntValue) || pA->u.iValue!=pB->u.iValue ){ return 2; } }else if( pA->op!=TK_COLUMN && ALWAYS(pA->op!=TK_AGG_COLUMN) && pA->u.zToken){ @@ -3846,50 +3850,72 @@ /* ** Compare two ExprList objects. Return 0 if they are identical and ** non-zero if they differ in any way. ** +** If any subelement of pB has Expr.iTable==(-1) then it is allowed +** to compare equal to an equivalent element in pA with Expr.iTable==iTab. +** ** This routine might return non-zero for equivalent ExprLists. The ** only consequence will be disabled optimizations. But this routine ** must never return 0 if the two ExprList objects are different, or ** a malfunction will result. ** ** Two NULL pointers are considered to be the same. But a NULL pointer ** always differs from a non-NULL pointer. */ -int sqlite3ExprListCompare(ExprList *pA, ExprList *pB){ +int sqlite3ExprListCompare(ExprList *pA, ExprList *pB, int iTab){ int i; if( pA==0 && pB==0 ) return 0; if( pA==0 || pB==0 ) return 1; if( pA->nExpr!=pB->nExpr ) return 1; for(i=0; inExpr; i++){ Expr *pExprA = pA->a[i].pExpr; Expr *pExprB = pB->a[i].pExpr; if( pA->a[i].sortOrder!=pB->a[i].sortOrder ) return 1; - if( sqlite3ExprCompare(pExprA, pExprB) ) return 1; + if( sqlite3ExprCompare(pExprA, pExprB, iTab) ) return 1; } return 0; } /* ** Return true if we can prove the pE2 will always be true if pE1 is ** true. Return false if we cannot complete the proof or if pE2 might ** be false. Examples: ** -** pE1: x==5 pE2: x>0 Result: true -** pE1: x>0 pE2: x==5 Result: false -** pE1: x!=123 pE2: x IS NOT NULL Result: true +** pE1: x==5 pE2: x==5 Result: true +** pE1: x>0 pE2: x==5 Result: false +** pE1: x=21 pE2: x=21 OR y=43 Result: true +** pE1: x!=123 pE2: x IS NOT NULL Result: true +** pE1: x!=?1 pE2: x IS NOT NULL Result: true +** pE1: x IS NULL pE2: x IS NOT NULL Result: false +** pE1: x IS ?2 pE2: x IS NOT NULL Reuslt: false ** ** When comparing TK_COLUMN nodes between pE1 and pE2, if pE2 has ** Expr.iTable<0 then assume a table number given by iTab. ** ** When in doubt, return false. Returning true might give a performance ** improvement. Returning false might cause a performance reduction, but ** it will always give the correct answer and is hence always safe. */ int sqlite3ExprImpliesExpr(Expr *pE1, Expr *pE2, int iTab){ - return 0; /* FIXME: this needs to be worked out */ + if( sqlite3ExprCompare(pE1, pE2, iTab)==0 ){ + return 1; + } + if( pE2->op==TK_OR + && (sqlite3ExprImpliesExpr(pE1, pE2->pLeft, iTab) + || sqlite3ExprImpliesExpr(pE1, pE2->pRight, iTab) ) + ){ + return 1; + } + if( pE2->op==TK_NOTNULL + && sqlite3ExprCompare(pE1->pLeft, pE2->pLeft, iTab)==0 + && (pE1->op!=TK_ISNULL && pE1->op!=TK_IS) + ){ + return 1; + } + return 0; } /* ** An instance of the following structure is used by the tree walker ** to count references to table columns in the arguments of an @@ -4068,11 +4094,11 @@ /* Check to see if pExpr is a duplicate of another aggregate ** function that is already in the pAggInfo structure */ struct AggInfo_func *pItem = pAggInfo->aFunc; for(i=0; inFunc; i++, pItem++){ - if( sqlite3ExprCompare(pItem->pExpr, pExpr)==0 ){ + if( sqlite3ExprCompare(pItem->pExpr, pExpr, -1)==0 ){ break; } } if( i>=pAggInfo->nFunc ){ /* pExpr is original. Make a new entry in pAggInfo->aFunc[] Index: src/insert.c ================================================================== --- src/insert.c +++ src/insert.c @@ -1646,11 +1646,11 @@ } if( !xferCompatibleCollation(pSrc->azColl[i],pDest->azColl[i]) ){ return 0; /* Different collating sequences */ } } - if( sqlite3ExprCompare(pSrc->pPartIdxWhere, pDest->pPartIdxWhere) ){ + if( sqlite3ExprCompare(pSrc->pPartIdxWhere, pDest->pPartIdxWhere, -1) ){ return 0; /* Different WHERE clauses */ } /* If no test above fails then the indices must be compatible */ return 1; @@ -1804,11 +1804,11 @@ if( pSrcIdx==0 ){ return 0; /* pDestIdx has no corresponding index in pSrc */ } } #ifndef SQLITE_OMIT_CHECK - if( pDest->pCheck && sqlite3ExprListCompare(pSrc->pCheck, pDest->pCheck) ){ + if( pDest->pCheck && sqlite3ExprListCompare(pSrc->pCheck,pDest->pCheck,-1) ){ return 0; /* Tables have different CHECK constraints. Ticket #2252 */ } #endif #ifndef SQLITE_OMIT_FOREIGN_KEY /* Disallow the transfer optimization if the destination table constains Index: src/resolve.c ================================================================== --- src/resolve.c +++ src/resolve.c @@ -823,11 +823,11 @@ /* Try to match the ORDER BY expression against an expression ** in the result set. Return an 1-based index of the matching ** result-set entry. */ for(i=0; inExpr; i++){ - if( sqlite3ExprCompare(pEList->a[i].pExpr, pE)<2 ){ + if( sqlite3ExprCompare(pEList->a[i].pExpr, pE, -1)<2 ){ return i+1; } } /* If no match, return 0. */ @@ -1051,11 +1051,11 @@ pItem->iOrderByCol = 0; if( sqlite3ResolveExprNames(pNC, pE) ){ return 1; } for(j=0; jpEList->nExpr; j++){ - if( sqlite3ExprCompare(pE, pSelect->pEList->a[j].pExpr)==0 ){ + if( sqlite3ExprCompare(pE, pSelect->pEList->a[j].pExpr, -1)==0 ){ pItem->iOrderByCol = j+1; } } } return sqlite3ResolveOrderGroupBy(pParse, pSelect, pOrderBy, zType); Index: src/select.c ================================================================== --- src/select.c +++ src/select.c @@ -4175,11 +4175,11 @@ ** will cause elements to come out in the correct order. This is ** an optimization - the correct answer should result regardless. ** Use the SQLITE_GroupByOrder flag with SQLITE_TESTCTRL_OPTIMIZER ** to disable this optimization for testing purposes. */ - if( sqlite3ExprListCompare(p->pGroupBy, pOrderBy)==0 + if( sqlite3ExprListCompare(p->pGroupBy, pOrderBy, -1)==0 && OptimizationEnabled(db, SQLITE_GroupByOrder) ){ pOrderBy = 0; } /* If the query is DISTINCT with an ORDER BY but is not an aggregate, and @@ -4196,11 +4196,11 @@ ** used for both the ORDER BY and DISTINCT processing. As originally ** written the query must use a temp-table for at least one of the ORDER ** BY and DISTINCT, and an index or separate temp-table for the other. */ if( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct - && sqlite3ExprListCompare(pOrderBy, p->pEList)==0 + && sqlite3ExprListCompare(pOrderBy, p->pEList, -1)==0 ){ p->selFlags &= ~SF_Distinct; p->pGroupBy = sqlite3ExprListDup(db, p->pEList, 0); pGroupBy = p->pGroupBy; pOrderBy = 0; Index: src/sqliteInt.h ================================================================== --- src/sqliteInt.h +++ src/sqliteInt.h @@ -2832,12 +2832,12 @@ void sqlite3UnlinkAndDeleteTable(sqlite3*,int,const char*); void sqlite3UnlinkAndDeleteIndex(sqlite3*,int,const char*); void sqlite3Vacuum(Parse*); int sqlite3RunVacuum(char**, sqlite3*); char *sqlite3NameFromToken(sqlite3*, Token*); -int sqlite3ExprCompare(Expr*, Expr*); -int sqlite3ExprListCompare(ExprList*, ExprList*); +int sqlite3ExprCompare(Expr*, Expr*, int); +int sqlite3ExprListCompare(ExprList*, ExprList*, int); int sqlite3ExprImpliesExpr(Expr*, Expr*, int); void sqlite3ExprAnalyzeAggregates(NameContext*, Expr*); void sqlite3ExprAnalyzeAggList(NameContext*,ExprList*); int sqlite3FunctionUsesThisSrc(Expr*, SrcList*); Vdbe *sqlite3GetVdbe(Parse*);