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Loop through the elements on the RHS of an IN operator in reverse order when

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the ORDER BY clauses specifies DESC.

FossilOrigin-Name: f78395c8896666bb1359b83fbcd58d5e3dbc39d3
This commit is contained in:
drh
2013-02-08 18:48:23 +00:00
parent c3e552ff5c
commit 2d96b934c8
6 changed files with 43 additions and 24 deletions
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14
src/where.c
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@@ -3008,15 +3008,7 @@ static int isSortingIndex(
if( pConstraint==0 ){
isEq = 0;
}else if( (pConstraint->eOperator & WO_IN)!=0 ){
#if 0
/* Constraints of the form: "X IN ..." cannot be used with an ORDER BY
** because we do not know in what order the values on the RHS of the IN
** operator will occur. */
break;
#else
if( termSortOrder ) break;
isEq = 0;
#endif
}else if( (pConstraint->eOperator & WO_ISNULL)!=0 ){
uniqueNotNull = 0;
isEq = 1; /* "X IS NULL" means X has only a single value */
@@ -3786,12 +3778,13 @@ static int codeEqualityTerm(
int eType;
int iTab;
struct InLoop *pIn;
u8 bRev = (pLevel->plan.wsFlags & WHERE_REVERSE)!=0;
assert( pX->op==TK_IN );
iReg = iTarget;
eType = sqlite3FindInIndex(pParse, pX, 0);
iTab = pX->iTable;
sqlite3VdbeAddOp2(v, OP_Rewind, iTab, 0);
sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iTab, 0);
assert( pLevel->plan.wsFlags & WHERE_IN_ABLE );
if( pLevel->u.in.nIn==0 ){
pLevel->addrNxt = sqlite3VdbeMakeLabel(v);
@@ -3809,6 +3802,7 @@ static int codeEqualityTerm(
}else{
pIn->addrInTop = sqlite3VdbeAddOp3(v, OP_Column, iTab, 0, iReg);
}
pIn->eEndLoopOp = bRev ? OP_Prev : OP_Next;
sqlite3VdbeAddOp1(v, OP_IsNull, iReg);
}else{
pLevel->u.in.nIn = 0;
@@ -5550,7 +5544,7 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
sqlite3VdbeResolveLabel(v, pLevel->addrNxt);
for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){
sqlite3VdbeJumpHere(v, pIn->addrInTop+1);
sqlite3VdbeAddOp2(v, OP_Next, pIn->iCur, pIn->addrInTop);
sqlite3VdbeAddOp2(v, pIn->eEndLoopOp, pIn->iCur, pIn->addrInTop);
sqlite3VdbeJumpHere(v, pIn->addrInTop-1);
}
sqlite3DbFree(db, pLevel->u.in.aInLoop);