diff options
Diffstat (limited to 'src/resolve.c')
| -rw-r--r-- | src/resolve.c | 147 |
1 files changed, 108 insertions, 39 deletions
diff --git a/src/resolve.c b/src/resolve.c index 30785ca70..4d5e23dff 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". @@ -208,6 +192,29 @@ Bitmask sqlite3ExprColUsed(Expr *pExpr){ } /* +** Create a new expression term for the column specified by pMatch and +** iColumn. Append this new expression term to the FULL JOIN Match set +** in *ppList. Create a new *ppList if this is the first term in the +** set. +*/ +static void extendFJMatch( + Parse *pParse, /* Parsing context */ + ExprList **ppList, /* ExprList to extend */ + SrcItem *pMatch, /* Source table containing the column */ + i16 iColumn /* The column number */ +){ + Expr *pNew = sqlite3ExprAlloc(pParse->db, TK_COLUMN, 0, 0); + if( pNew ){ + pNew->iTable = pMatch->iCursor; + pNew->iColumn = iColumn; + pNew->y.pTab = pMatch->pTab; + assert( (pMatch->fg.jointype & (JT_LEFT|JT_LTORJ))!=0 ); + ExprSetProperty(pNew, EP_CanBeNull); + *ppList = sqlite3ExprListAppend(pParse, *ppList, pNew); + } +} + +/* ** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up ** that name in the set of source tables in pSrcList and make the pExpr ** expression node refer back to that source column. The following changes @@ -252,8 +259,9 @@ static int lookupName( NameContext *pTopNC = pNC; /* First namecontext in the list */ Schema *pSchema = 0; /* Schema of the expression */ int eNewExprOp = TK_COLUMN; /* New value for pExpr->op on success */ - Table *pTab = 0; /* Table hold the row */ + Table *pTab = 0; /* Table holding the row */ Column *pCol; /* A column of pTab */ + ExprList *pFJMatch = 0; /* Matches for FULL JOIN .. USING */ assert( pNC ); /* the name context cannot be NULL. */ assert( zCol ); /* The Z in X.Y.Z cannot be NULL */ @@ -310,6 +318,30 @@ static int lookupName( pEList = pItem->pSelect->pEList; for(j=0; j<pEList->nExpr; j++){ if( sqlite3MatchEName(&pEList->a[j], zCol, zTab, zDb) ){ + if( cnt>0 ){ + if( pItem->fg.isUsing==0 + || sqlite3IdListIndex(pItem->u3.pUsing, zCol)<0 + ){ + /* Two or more tables have the same column name which is + ** not joined by USING. This is an error. Signal as much + ** by clearing pFJMatch and letting cnt go above 1. */ + sqlite3ExprListDelete(db, pFJMatch); + pFJMatch = 0; + }else + if( (pItem->fg.jointype & JT_RIGHT)==0 ){ + /* An INNER or LEFT JOIN. Use the left-most table */ + continue; + }else + if( (pItem->fg.jointype & JT_LEFT)==0 ){ + /* A RIGHT JOIN. Use the right-most table */ + cnt = 0; + sqlite3ExprListDelete(db, pFJMatch); + pFJMatch = 0; + }else{ + /* For a FULL JOIN, we must construct a coalesce() func */ + extendFJMatch(pParse, &pFJMatch, pMatch, pExpr->iColumn); + } + } cnt++; cntTab = 2; pMatch = pItem; @@ -339,16 +371,28 @@ static int lookupName( if( pCol->hName==hCol && sqlite3StrICmp(pCol->zCnName, zCol)==0 ){ - /* If there has been exactly one prior match and this match - ** is for the right-hand table of a NATURAL JOIN or is in a - ** USING clause, then skip this match. - */ - if( cnt==1 ){ - if( pItem->fg.jointype & JT_NATURAL ) continue; - if( pItem->fg.isUsing - && nameInUsingClause(pItem->u3.pUsing, zCol) + if( cnt>0 ){ + if( pItem->fg.isUsing==0 + || sqlite3IdListIndex(pItem->u3.pUsing, zCol)<0 ){ + /* Two or more tables have the same column name which is + ** not joined by USING. This is an error. Signal as much + ** by clearing pFJMatch and letting cnt go above 1. */ + sqlite3ExprListDelete(db, pFJMatch); + pFJMatch = 0; + }else + if( (pItem->fg.jointype & JT_RIGHT)==0 ){ + /* An INNER or LEFT JOIN. Use the left-most table */ continue; + }else + if( (pItem->fg.jointype & JT_LEFT)==0 ){ + /* A RIGHT JOIN. Use the right-most table */ + cnt = 0; + sqlite3ExprListDelete(db, pFJMatch); + pFJMatch = 0; + }else{ + /* For a FULL JOIN, we must construct a coalesce() func */ + extendFJMatch(pParse, &pFJMatch, pMatch, pExpr->iColumn); } } cnt++; @@ -367,9 +411,7 @@ static int lookupName( pExpr->iTable = pMatch->iCursor; assert( ExprUseYTab(pExpr) ); pExpr->y.pTab = pMatch->pTab; - /* RIGHT JOIN not (yet) supported */ - assert( (pMatch->fg.jointype & JT_RIGHT)==0 ); - if( (pMatch->fg.jointype & JT_LEFT)!=0 ){ + if( (pMatch->fg.jointype & (JT_LEFT|JT_LTORJ))!=0 ){ ExprSetProperty(pExpr, EP_CanBeNull); } pSchema = pExpr->y.pTab->pSchema; @@ -610,11 +652,37 @@ static int lookupName( } /* - ** cnt==0 means there was not match. cnt>1 means there were two or - ** more matches. Either way, we have an error. + ** cnt==0 means there was not match. + ** cnt>1 means there were two or more matches. + ** + ** cnt==0 is always an error. cnt>1 is often an error, but might + ** be multiple matches for a NATURAL LEFT JOIN or a LEFT JOIN USING. */ + assert( pFJMatch==0 || cnt>0 ); + assert( !ExprHasProperty(pExpr, EP_xIsSelect|EP_IntValue) ); if( cnt!=1 ){ const char *zErr; + if( pFJMatch ){ + if( pFJMatch->nExpr==cnt-1 ){ + if( ExprHasProperty(pExpr,EP_Leaf) ){ + ExprClearProperty(pExpr,EP_Leaf); + }else{ + sqlite3ExprDelete(db, pExpr->pLeft); + pExpr->pLeft = 0; + sqlite3ExprDelete(db, pExpr->pRight); + pExpr->pRight = 0; + } + extendFJMatch(pParse, &pFJMatch, pMatch, pExpr->iColumn); + pExpr->op = TK_FUNCTION; + pExpr->u.zToken = "coalesce"; + pExpr->x.pList = pFJMatch; + cnt = 1; + goto lookupname_end; + }else{ + sqlite3ExprListDelete(db, pFJMatch); + pFJMatch = 0; + } + } zErr = cnt==0 ? "no such column" : "ambiguous column name"; if( zDb ){ sqlite3ErrorMsg(pParse, "%s: %s.%s.%s", zErr, zDb, zTab, zCol); @@ -627,6 +695,16 @@ static int lookupName( pParse->checkSchema = 1; pTopNC->nNcErr++; } + assert( pFJMatch==0 ); + + /* Remove all substructure from pExpr */ + if( !ExprHasProperty(pExpr,(EP_TokenOnly|EP_Leaf)) ){ + sqlite3ExprDelete(db, pExpr->pLeft); + pExpr->pLeft = 0; + sqlite3ExprDelete(db, pExpr->pRight); + pExpr->pRight = 0; + ExprSetProperty(pExpr, EP_Leaf); + } /* If a column from a table in pSrcList is referenced, then record ** this fact in the pSrcList.a[].colUsed bitmask. Column 0 causes @@ -646,16 +724,7 @@ static int lookupName( pMatch->colUsed |= sqlite3ExprColUsed(pExpr); } - /* Clean up and return - */ - if( !ExprHasProperty(pExpr,(EP_TokenOnly|EP_Leaf)) ){ - sqlite3ExprDelete(db, pExpr->pLeft); - pExpr->pLeft = 0; - sqlite3ExprDelete(db, pExpr->pRight); - pExpr->pRight = 0; - } pExpr->op = eNewExprOp; - ExprSetProperty(pExpr, EP_Leaf); lookupname_end: if( cnt==1 ){ assert( pNC!=0 ); |