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COUNT(DISTINCT x) is now fully functional, though it could benefit from

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additional testing. (CVS 2688)

FossilOrigin-Name: 2f397bd8142ec5e8f7238127012d14fdb558d918
This commit is contained in:
drh
2005-09-11 11:56:27 +00:00
parent 00b950d71e
commit c99130fd82
7 changed files with 122 additions and 35 deletions
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68
src/select.c
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@@ -12,7 +12,7 @@
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.267 2005/09/10 15:28:09 drh Exp $
** $Id: select.c,v 1.268 2005/09/11 11:56:28 drh Exp $
*/
#include "sqliteInt.h"
@@ -364,6 +364,34 @@ static void codeLimiter(
}
}
/*
** Add code that will check to make sure the top N elements of the
** stack are distinct. iTab is a sorting index that holds previously
** seen combinations of the N values. A new entry is made in iTab
** if the current N values are new.
**
** A jump to addrRepeat is made and the K values are popped from the
** stack if the top N elements are not distinct.
*/
static void codeDistinct(
Vdbe *v, /* Generate code into this VM */
int iTab, /* A sorting index used to test for distinctness */
int addrRepeat, /* Jump to here if not distinct */
int N, /* The top N elements of the stack must be distinct */
int K /* Pop K elements from the stack if indistinct */
){
#if NULL_ALWAYS_DISTINCT
sqlite3VdbeAddOp(v, OP_IsNull, -N, sqlite3VdbeCurrentAddr(v)+6);
#endif
sqlite3VdbeAddOp(v, OP_MakeRecord, -N, 0);
sqlite3VdbeAddOp(v, OP_Distinct, iTab, sqlite3VdbeCurrentAddr(v)+3);
sqlite3VdbeAddOp(v, OP_Pop, K, 0);
sqlite3VdbeAddOp(v, OP_Goto, 0, addrRepeat);
VdbeComment((v, "# skip indistinct records"));
sqlite3VdbeAddOp(v, OP_IdxInsert, iTab, 0);
}
/*
** This routine generates the code for the inside of the inner loop
** of a SELECT.
@@ -419,17 +447,7 @@ static int selectInnerLoop(
*/
if( hasDistinct ){
int n = pEList->nExpr;
#if NULL_ALWAYS_DISTINCT
sqlite3VdbeAddOp(v, OP_IsNull, -pEList->nExpr, sqlite3VdbeCurrentAddr(v)+7);
#endif
/* Deliberately leave the affinity string off of the following
** OP_MakeRecord */
sqlite3VdbeAddOp(v, OP_MakeRecord, -n, 0);
sqlite3VdbeAddOp(v, OP_Distinct, distinct, sqlite3VdbeCurrentAddr(v)+3);
sqlite3VdbeAddOp(v, OP_Pop, n+1, 0);
sqlite3VdbeAddOp(v, OP_Goto, 0, iContinue);
VdbeComment((v, "# skip indistinct records"));
sqlite3VdbeAddOp(v, OP_IdxInsert, distinct, 0);
codeDistinct(v, distinct, iContinue, n, n+1);
if( pOrderBy==0 ){
codeLimiter(v, p, iContinue, iBreak, nColumn);
}
@@ -2407,6 +2425,7 @@ static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){
Vdbe *v = pParse->pVdbe;
int i;
int addr;
struct AggInfo_func *pFunc;
if( pAggInfo->nFunc+pAggInfo->nColumn==0 ){
return;
}
@@ -2414,8 +2433,20 @@ static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){
for(i=0; i<pAggInfo->nColumn; i++){
addr = sqlite3VdbeAddOp(v, OP_MemStore, pAggInfo->aCol[i].iMem, 0);
}
for(i=0; i<pAggInfo->nFunc; i++){
addr = sqlite3VdbeAddOp(v, OP_MemStore, pAggInfo->aFunc[i].iMem, 0);
for(pFunc=pAggInfo->aFunc, i=0; i<pAggInfo->nFunc; i++, pFunc++){
addr = sqlite3VdbeAddOp(v, OP_MemStore, pFunc->iMem, 0);
if( pFunc->iDistinct>=0 ){
Expr *pE = pFunc->pExpr;
if( pE->pList==0 || pE->pList->nExpr!=1 ){
sqlite3ErrorMsg(pParse, "DISTINCT in aggregate must be followed "
"by an expression");
pFunc->iDistinct = -1;
}else{
KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pE->pList);
sqlite3VdbeOp3(v, OP_OpenVirtual, pFunc->iDistinct, 0,
(char*)pKeyInfo, P3_KEYINFO_HANDOFF);
}
}
}
sqlite3VdbeChangeP2(v, addr, 1);
}
@@ -2448,6 +2479,7 @@ static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
pAggInfo->directMode = 1;
for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
int nArg;
int addrNext = 0;
ExprList *pList = pF->pExpr->pList;
if( pList ){
nArg = pList->nExpr;
@@ -2455,6 +2487,11 @@ static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
}else{
nArg = 0;
}
if( pF->iDistinct>=0 ){
addrNext = sqlite3VdbeMakeLabel(v);
assert( nArg==1 );
codeDistinct(v, pF->iDistinct, addrNext, 1, 1);
}
if( pF->pFunc->needCollSeq ){
CollSeq *pColl = 0;
struct ExprList_item *pItem;
@@ -2468,6 +2505,9 @@ static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
sqlite3VdbeOp3(v, OP_CollSeq, 0, 0, (char *)pColl, P3_COLLSEQ);
}
sqlite3VdbeOp3(v, OP_AggStep, pF->iMem, nArg, (void*)pF->pFunc, P3_FUNCDEF);
if( addrNext ){
sqlite3VdbeResolveLabel(v, addrNext);
}
}
for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
sqlite3ExprCode(pParse, pC->pExpr);