diff options
Diffstat (limited to 'src/resolve.c')
| -rw-r--r-- | src/resolve.c | 38 |
1 files changed, 3 insertions, 35 deletions
diff --git a/src/resolve.c b/src/resolve.c index 22df22394..2c4212ba7 100644 --- a/src/resolve.c +++ b/src/resolve.c @@ -45,30 +45,6 @@ static void incrAggFunctionDepth(Expr *pExpr, int N){ ** Turn the pExpr expression into an alias for the iCol-th column of the ** result set in pEList. ** -** If the result set column is a simple column reference, then this routine -** makes an exact copy. But for any other kind of expression, this -** routine make a copy of the result set column as the argument to the -** TK_AS operator. The TK_AS operator causes the expression to be -** evaluated just once and then reused for each alias. -** -** The reason for suppressing the TK_AS term when the expression is a simple -** column reference is so that the column reference will be recognized as -** usable by indices within the WHERE clause processing logic. -** -** The TK_AS operator is inhibited if zType[0]=='G'. This means -** that in a GROUP BY clause, the expression is evaluated twice. Hence: -** -** SELECT random()%5 AS x, count(*) FROM tab GROUP BY x -** -** Is equivalent to: -** -** SELECT random()%5 AS x, count(*) FROM tab GROUP BY random()%5 -** -** The result of random()%5 in the GROUP BY clause is probably different -** from the result in the result-set. On the other hand Standard SQL does -** not allow the GROUP BY clause to contain references to result-set columns. -** So this should never come up in well-formed queries. -** ** If the reference is followed by a COLLATE operator, then make sure ** the COLLATE operator is preserved. For example: ** @@ -102,19 +78,11 @@ static void resolveAlias( db = pParse->db; pDup = sqlite3ExprDup(db, pOrig, 0); if( pDup==0 ) return; - if( pOrig->op!=TK_COLUMN && zType[0]!='G' ){ - incrAggFunctionDepth(pDup, nSubquery); - pDup = sqlite3PExpr(pParse, TK_AS, pDup, 0, 0); - if( pDup==0 ) return; - ExprSetProperty(pDup, EP_Skip); - if( pEList->a[iCol].u.x.iAlias==0 ){ - pEList->a[iCol].u.x.iAlias = (u16)(++pParse->nAlias); - } - pDup->iTable = pEList->a[iCol].u.x.iAlias; - } + if( zType[0]!='G' ) incrAggFunctionDepth(pDup, nSubquery); if( pExpr->op==TK_COLLATE ){ pDup = sqlite3ExprAddCollateString(pParse, pDup, pExpr->u.zToken); } + ExprSetProperty(pDup, EP_Alias); /* Before calling sqlite3ExprDelete(), set the EP_Static flag. This ** prevents ExprDelete() from deleting the Expr structure itself, @@ -506,7 +474,7 @@ static int lookupName( lookupname_end: if( cnt==1 ){ assert( pNC!=0 ); - if( pExpr->op!=TK_AS ){ + if( !ExprHasProperty(pExpr, EP_Alias) ){ sqlite3AuthRead(pParse, pExpr, pSchema, pNC->pSrcList); } /* Increment the nRef value on all name contexts from TopNC up to |