diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/resolve.c | 20 | ||||
| -rw-r--r-- | src/select.c | 159 |
2 files changed, 60 insertions, 119 deletions
diff --git a/src/resolve.c b/src/resolve.c index 09b16f1ad..0f0b85306 100644 --- a/src/resolve.c +++ b/src/resolve.c @@ -115,22 +115,6 @@ static void resolveAlias( } } - -/* -** Return TRUE if the name zCol occurs anywhere in the USING clause. -** -** Return FALSE if the USING clause is NULL or if it does not contain -** zCol. -*/ -static int nameInUsingClause(IdList *pUsing, const char *zCol){ - int k; - assert( pUsing!=0 ); - for(k=0; k<pUsing->nId; k++){ - if( sqlite3StrICmp(pUsing->a[k].zName, zCol)==0 ) return 1; - } - return 0; -} - /* ** Subqueries stores the original database, table and column names for their ** result sets in ExprList.a[].zSpan, in the form "DATABASE.TABLE.COLUMN". @@ -338,7 +322,7 @@ static int lookupName( if( sqlite3MatchEName(&pEList->a[j], zCol, zTab, zDb) ){ if( cnt>0 ){ if( pItem->fg.isUsing==0 - || !nameInUsingClause(pItem->u3.pUsing, zCol) + || sqlite3IdListIndex(pItem->u3.pUsing, zCol)<0 ){ sqlite3ExprListDelete(db, pFJMatch); pFJMatch = 0; @@ -392,7 +376,7 @@ static int lookupName( ){ if( cnt>0 ){ if( pItem->fg.isUsing==0 - || !nameInUsingClause(pItem->u3.pUsing, zCol) + || sqlite3IdListIndex(pItem->u3.pUsing, zCol)<0 ){ sqlite3ExprListDelete(db, pFJMatch); pFJMatch = 0; diff --git a/src/select.c b/src/select.c index f6938ccab..db4117209 100644 --- a/src/select.c +++ b/src/select.c @@ -320,11 +320,9 @@ int sqlite3ColumnIndex(Table *pTab, const char *zCol){ } /* -** Search the first N tables in pSrc, looking for a -** table that has a column named zCol. -** -** Search left-to-right if bRightmost is false. Search right-to-left -** if bRightmost is true. +** Search the tables iStart..iEnd (inclusive) in pSrc, looking for a +** table that has a column named zCol. The search is left-to-right. +** The first match found is returned. ** ** When found, set *piTab and *piCol to the table index and column index ** of the matching column and return TRUE. @@ -333,21 +331,21 @@ int sqlite3ColumnIndex(Table *pTab, const char *zCol){ */ static int tableAndColumnIndex( SrcList *pSrc, /* Array of tables to search */ - int N, /* Number of tables in pSrc->a[] to search */ + int iStart, /* First member of pSrc->a[] to check */ + int iEnd, /* Last member of pSrc->a[] to check */ const char *zCol, /* Name of the column we are looking for */ int *piTab, /* Write index of pSrc->a[] here */ int *piCol, /* Write index of pSrc->a[*piTab].pTab->aCol[] here */ - int bIgnoreHidden, /* True to ignore hidden columns */ - int bRightmost /* Return the right-most match */ + int bIgnoreHidden /* Ignore hidden columns */ ){ int i; /* For looping over tables in pSrc */ int iCol; /* Index of column matching zCol */ - int rc = 0; - assert( N<=pSrc->nSrc ); - + assert( iEnd<pSrc->nSrc ); + assert( iStart>=0 ); assert( (piTab==0)==(piCol==0) ); /* Both or neither are NULL */ - for(i=0; i<N; i++){ + + for(i=iStart; i<=iEnd; i++){ iCol = sqlite3ColumnIndex(pSrc->a[i].pTab, zCol); if( iCol>=0 && (bIgnoreHidden==0 || IsHiddenColumn(&pSrc->a[i].pTab->aCol[iCol])==0) @@ -356,58 +354,10 @@ static int tableAndColumnIndex( *piTab = i; *piCol = iCol; } - rc = 1; - if( !bRightmost ) break; + return 1; } } - return rc; -} - -/* -** This function is used to add terms implied by JOIN syntax to the -** WHERE clause expression of a SELECT statement. The new term, which -** is ANDed with the existing WHERE clause, is of the form: -** -** (tab1.col1 = tab2.col2) -** -** where tab1 is the iSrc'th table in SrcList pSrc and tab2 is the -** (iSrc+1)'th. Column col1 is column iColLeft of tab1, and col2 is -** column iColRight of tab2. -*/ -static void addWhereTerm( - Parse *pParse, /* Parsing context */ - SrcList *pSrc, /* List of tables in FROM clause */ - int iLeft, /* Index of first table to join in pSrc */ - int iColLeft, /* Index of column in first table */ - int iRight, /* Index of second table in pSrc */ - int iColRight, /* Index of column in second table */ - u32 joinType, /* EP_FromJoin or EP_InnerJoin */ - Expr **ppWhere /* IN/OUT: The WHERE clause to add to */ -){ - sqlite3 *db = pParse->db; - Expr *pE1; - Expr *pE2; - Expr *pEq; - - assert( iLeft<iRight ); - assert( pSrc->nSrc>iRight ); - assert( pSrc->a[iLeft].pTab ); - assert( pSrc->a[iRight].pTab ); - - pE1 = sqlite3CreateColumnExpr(db, pSrc, iLeft, iColLeft); - pE2 = sqlite3CreateColumnExpr(db, pSrc, iRight, iColRight); - - pEq = sqlite3PExpr(pParse, TK_EQ, pE1, pE2); - assert( pE2!=0 || pEq==0 ); /* Due to db->mallocFailed test - ** in sqlite3DbMallocRawNN() called from - ** sqlite3PExpr(). */ - if( pEq ){ - ExprSetProperty(pEq, joinType); - assert( !ExprHasProperty(pEq, EP_TokenOnly|EP_Reduced) ); - ExprSetVVAProperty(pEq, EP_NoReduce); - pEq->w.iJoin = pE2->iTable; - } - *ppWhere = sqlite3ExprAnd(pParse, *ppWhere, pEq); + return 0; } /* @@ -532,7 +482,7 @@ static int sqlite3ProcessJoin(Parse *pParse, Select *p){ if( IsHiddenColumn(&pRightTab->aCol[j]) ) continue; zName = pRightTab->aCol[j].zCnName; - if( tableAndColumnIndex(pSrc, i+1, zName, 0, 0, 1, 0) ){ + if( tableAndColumnIndex(pSrc, 0, i, zName, 0, 0, 1) ){ Token x; x.z = zName; x.n = sqlite3Strlen30(zName); @@ -555,64 +505,71 @@ static int sqlite3ProcessJoin(Parse *pParse, Select *p){ */ if( pRight->fg.isUsing ){ IdList *pList = pRight->u3.pUsing; - int bRight = (pLeft->fg.jointype & JT_RIGHT)!=0; + sqlite3 *db = pParse->db; assert( pList!=0 ); for(j=0; j<pList->nId; j++){ char *zName; /* Name of the term in the USING clause */ int iLeft; /* Table on the left with matching column name */ int iLeftCol; /* Column number of matching column on the left */ int iRightCol; /* Column number of matching column on the right */ - int iNxLeft, iNxLeftCol; + Expr *pE1; /* Reference to the column on the LEFT of the join */ + Expr *pE2; /* Reference to the column on the RIGHT of the join */ + Expr *pEq; /* Equality constraint. pE1 == pE2 */ zName = pList->a[j].zName; iRightCol = sqlite3ColumnIndex(pRightTab, zName); if( iRightCol<0 - || !tableAndColumnIndex(pSrc, i+1, zName, &iLeft, &iLeftCol, - pRight->fg.isSynthUsing, bRight) + || tableAndColumnIndex(pSrc, 0, i, zName, &iLeft, &iLeftCol, + pRight->fg.isSynthUsing)==0 ){ sqlite3ErrorMsg(pParse, "cannot join using column %s - column " "not present in both tables", zName); return 1; } - if( (pLeft->fg.jointype & (JT_RIGHT|JT_LEFT))!=(JT_LEFT|JT_RIGHT) - || 0==tableAndColumnIndex(pSrc, iLeft, zName, &iNxLeft, &iNxLeftCol, - pRight->fg.isSynthUsing, 1) - ){ - addWhereTerm(pParse, pSrc, iLeft, iLeftCol, i+1, iRightCol, - joinType, &p->pWhere); - }else{ - /* Because the left-hand side of this join is another RIGHT or FULL - ** JOIN with two or more tables hold zName, we need to construct - ** a coalesce() function for left side of the ON constraint. + pE1 = sqlite3CreateColumnExpr(db, pSrc, iLeft, iLeftCol); + if( (pSrc->a[0].fg.jointype & JT_LTORJ)!=0 ){ + /* This branch runs if the query contains one or more RIGHT or FULL + ** JOINs. If only a single table on the left side of this join + ** contains the zName column, then this routine is branch is + ** a no-op. But if there are two or more tables on the left side + ** of the join, construct a coalesce() function that gathers all + ** such tables. Raise an error if more than one of those references + ** to zName is not also within a prior USING clause. + ** + ** We really ought to raise an error if there are two or more + ** non-USING references to zName on the left of an INNER or LEFT + ** JOIN. But older versions of SQLite do not do that, so we avoid + ** adding a new error so as to not break legacy applications. */ - ExprList *pList; - Expr *pE; - Expr *pE2; - Expr *pEq; - sqlite3 *db = pParse->db; + ExprList *pFuncArgs = 0; /* Arguments to the coalesce() */ static const Token tkCoalesce = { "coalesce", 8 }; - pE = sqlite3CreateColumnExpr(db, pSrc, iLeft, iLeftCol); - pList = sqlite3ExprListAppend(pParse, 0, pE); - pE = sqlite3CreateColumnExpr(db, pSrc, iNxLeft, iNxLeftCol); - pList = sqlite3ExprListAppend(pParse, pList, pE); - while( tableAndColumnIndex(pSrc, iNxLeft, zName, - &iNxLeft, &iNxLeftCol, - pRight->fg.isSynthUsing, 1)!=0 ){ - pE = sqlite3CreateColumnExpr(db, pSrc, iNxLeft, iNxLeftCol); - pList = sqlite3ExprListAppend(pParse, pList, pE); + while( tableAndColumnIndex(pSrc, iLeft+1, i, zName, &iLeft, &iLeftCol, + pRight->fg.isSynthUsing)!=0 ){ + if( pSrc->a[iLeft].fg.isUsing==0 + || sqlite3IdListIndex(pSrc->a[iLeft].u3.pUsing, zName)<0 + ){ + sqlite3ErrorMsg(pParse, "ambiguous reference to %s in USING()", + zName); + break; + } + pFuncArgs = sqlite3ExprListAppend(pParse, pFuncArgs, pE1); + pE1 = sqlite3CreateColumnExpr(db, pSrc, iLeft, iLeftCol); } - pE = sqlite3ExprFunction(pParse, pList, &tkCoalesce, 0); - pE2 = sqlite3CreateColumnExpr(db, pSrc, i+1, iRightCol); - pEq = sqlite3PExpr(pParse, TK_EQ, pE, pE2); - assert( pE2!=0 || pEq==0 ); - if( pEq ){ - ExprSetProperty(pEq, joinType); - assert( !ExprHasProperty(pEq, EP_TokenOnly|EP_Reduced) ); - ExprSetVVAProperty(pEq, EP_NoReduce); - pEq->w.iJoin = pE2->iTable; + if( pFuncArgs ){ + pFuncArgs = sqlite3ExprListAppend(pParse, pFuncArgs, pE1); + pE1 = sqlite3ExprFunction(pParse, pFuncArgs, &tkCoalesce, 0); } - p->pWhere = sqlite3ExprAnd(pParse, p->pWhere, pEq); } + pE2 = sqlite3CreateColumnExpr(db, pSrc, i+1, iRightCol); + pEq = sqlite3PExpr(pParse, TK_EQ, pE1, pE2); + assert( pE2!=0 || pEq==0 ); + if( pEq ){ + ExprSetProperty(pEq, joinType); + assert( !ExprHasProperty(pEq, EP_TokenOnly|EP_Reduced) ); + ExprSetVVAProperty(pEq, EP_NoReduce); + pEq->w.iJoin = pE2->iTable; + } + p->pWhere = sqlite3ExprAnd(pParse, p->pWhere, pEq); } } |