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Allow min() and max() to be used as window functions.

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FossilOrigin-Name: c16125a884a9131b707ac20033968c4c3177ea79625a15efb64d754568c6c7a0
This commit is contained in:
dan
2018-05-30 20:44:58 +00:00
parent d6f784ef92
commit c9a8668ac7
8 changed files with 495 additions and 134 deletions
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115
src/window.c
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@@ -66,6 +66,28 @@ int sqlite3WindowCompare(Parse *pParse, Window *p1, Window *p2){
return 0;
}
static void windowAggInit(Parse *pParse, Window *pMWin){
Window *pWin;
for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
int funcFlags = pWin->pFunc->funcFlags;
if( (funcFlags & SQLITE_FUNC_MINMAX) && pWin->eStart!=TK_UNBOUNDED ){
ExprList *pList = pWin->pOwner->x.pList;
KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pList, 0, 0);
Vdbe *v = sqlite3GetVdbe(pParse);
pWin->csrApp = pParse->nTab++;
pWin->regApp = pParse->nMem+1;
pParse->nMem += 3;
if( pKeyInfo && pWin->pFunc->zName[1]=='i' ){
assert( pKeyInfo->aSortOrder[0]==0 );
pKeyInfo->aSortOrder[0] = 1;
}
sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pWin->csrApp, 2);
sqlite3VdbeAppendP4(v, pKeyInfo, P4_KEYINFO);
sqlite3VdbeAddOp2(v, OP_Integer, 0, pWin->regApp+1);
}
}
}
void sqlite3WindowCodeInit(Parse *pParse, Window *pWin){
Vdbe *v = sqlite3GetVdbe(pParse);
int nPart = (pWin->pPartition ? pWin->pPartition->nExpr : 0);
@@ -75,6 +97,7 @@ void sqlite3WindowCodeInit(Parse *pParse, Window *pWin){
pParse->nMem += nPart;
sqlite3VdbeAddOp3(v, OP_Null, 0, pWin->regPart, pWin->regPart+nPart-1);
}
windowAggInit(pParse, pWin);
}
static void windowCheckFrameValue(Parse *pParse, int reg, int bEnd){
@@ -85,7 +108,6 @@ static void windowCheckFrameValue(Parse *pParse, int reg, int bEnd){
Vdbe *v = sqlite3GetVdbe(pParse);
int regZero = ++pParse->nMem;
sqlite3VdbeAddOp2(v, OP_Integer, 0, regZero);
sqlite3VdbeAddOp2(v, OP_MustBeInt, reg, sqlite3VdbeCurrentAddr(v)+2);
sqlite3VdbeAddOp3(v, OP_Ge, regZero, sqlite3VdbeCurrentAddr(v)+2, reg);
@@ -93,6 +115,11 @@ static void windowCheckFrameValue(Parse *pParse, int reg, int bEnd){
sqlite3VdbeAppendP4(v, (void*)azErr[bEnd], P4_STATIC);
}
/*
** Generate VM code to invoke either xStep() (if bInverse is 0) or
** xInverse (if bInverse is non-zero) for each window function in the
** linked list starting at pMWin.
*/
static void windowAggStep(
Parse *pParse,
Window *pMWin,
@@ -103,13 +130,38 @@ static void windowAggStep(
Vdbe *v = sqlite3GetVdbe(pParse);
Window *pWin;
for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
int i;
for(i=0; i<pWin->nArg; i++){
sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol+i, reg+i);
int regArg;
if( csr>=0 ){
int i;
for(i=0; i<pWin->nArg; i++){
sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol+i, reg+i);
}
regArg = reg;
}else{
regArg = reg + pWin->iArgCol;
}
if( pWin->csrApp ){
if( bInverse==0 ){
sqlite3VdbeAddOp2(v, OP_AddImm, pWin->regApp+1, 1);
sqlite3VdbeAddOp2(v, OP_SCopy, regArg, pWin->regApp);
sqlite3VdbeAddOp3(v, OP_MakeRecord, pWin->regApp, 2, pWin->regApp+2);
sqlite3VdbeAddOp2(v, OP_IdxInsert, pWin->csrApp, pWin->regApp+2);
}else{
sqlite3VdbeAddOp4Int(v, OP_SeekGE, pWin->csrApp, 0, regArg, 1);
sqlite3VdbeAddOp1(v, OP_Delete, pWin->csrApp);
sqlite3VdbeJumpHere(v, sqlite3VdbeCurrentAddr(v)-2);
}
}else{
if( pWin->pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL ){
CollSeq *pColl;
pColl = sqlite3ExprCollSeq(pParse, pWin->pOwner->x.pList->a[0].pExpr);
sqlite3VdbeAddOp4(v, OP_CollSeq, 0,0,0, (const char*)pColl, P4_COLLSEQ);
}
sqlite3VdbeAddOp3(v, OP_AggStep0, bInverse, regArg, pWin->regAccum);
sqlite3VdbeAppendP4(v, pWin->pFunc, P4_FUNCDEF);
sqlite3VdbeChangeP5(v, (u8)pWin->nArg);
}
sqlite3VdbeAddOp3(v, OP_AggStep0, bInverse, reg, pWin->regAccum);
sqlite3VdbeAppendP4(v, pWin->pFunc, P4_FUNCDEF);
sqlite3VdbeChangeP5(v, (u8)pWin->nArg);
}
}
@@ -118,15 +170,25 @@ static void windowAggFinal(Parse *pParse, Window *pMWin, int bFinal){
Window *pWin;
for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
if( bFinal==0 ){
if( pWin->csrApp ){
sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regResult);
}
sqlite3VdbeAddOp2(v, OP_AggFinal, pWin->regAccum, pWin->nArg);
sqlite3VdbeAppendP4(v, pWin->pFunc, P4_FUNCDEF);
if( bFinal ){
sqlite3VdbeAddOp2(v, OP_Copy, pWin->regAccum, pWin->regResult);
sqlite3VdbeAddOp1(v, OP_Last, pWin->csrApp);
sqlite3VdbeAddOp3(v, OP_Column, pWin->csrApp, 0, pWin->regResult);
sqlite3VdbeJumpHere(v, sqlite3VdbeCurrentAddr(v)-2);
if( bFinal ){
sqlite3VdbeAddOp1(v, OP_ResetSorter, pWin->csrApp);
}
}else{
sqlite3VdbeChangeP3(v, -1, pWin->regResult);
if( bFinal==0 ){
sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regResult);
}
sqlite3VdbeAddOp2(v, OP_AggFinal, pWin->regAccum, pWin->nArg);
sqlite3VdbeAppendP4(v, pWin->pFunc, P4_FUNCDEF);
if( bFinal ){
sqlite3VdbeAddOp2(v, OP_Copy, pWin->regAccum, pWin->regResult);
}else{
sqlite3VdbeChangeP3(v, -1, pWin->regResult);
}
}
}
}
@@ -333,13 +395,12 @@ static void windowCodeRowExprStep(
if( pMWin->pPartition ){
ExprList *pPart = pMWin->pPartition;
int nPart = (pPart ? pPart->nExpr : 0);
int addrJump = 0;
int regNewPart = reg + pMWin->nBufferCol;
KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pPart, 0, 0);
addr = sqlite3VdbeAddOp3(v, OP_Compare, regNewPart, pMWin->regPart,nPart);
sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
addrJump = sqlite3VdbeAddOp3(v, OP_Jump, addr+2, addr+4, addr+2);
sqlite3VdbeAddOp3(v, OP_Jump, addr+2, addr+4, addr+2);
sqlite3VdbeAddOp2(v, OP_Gosub, regFlushPart, lblFlushPart);
sqlite3VdbeAddOp3(v, OP_Copy, regNewPart, pMWin->regPart, nPart);
}
@@ -355,7 +416,7 @@ static void windowCodeRowExprStep(
sqlite3VdbeAddOp2(v, OP_Gosub, regFlushPart, lblFlushPart);
addrGoto = sqlite3VdbeAddOp0(v, OP_Goto);
/* flush_partition: */
/* Start of "flush_partition" */
sqlite3VdbeResolveLabel(v, lblFlushPart);
sqlite3VdbeAddOp2(v, OP_Once, 0, sqlite3VdbeCurrentAddr(v)+3);
sqlite3VdbeAddOp2(v, OP_OpenDup, csrStart, pMWin->iEphCsr);
@@ -370,12 +431,18 @@ static void windowCodeRowExprStep(
if( pMWin->pEnd ){
sqlite3ExprCode(pParse, pMWin->pEnd, regEnd);
windowCheckFrameValue(pParse, regEnd, 1);
if( pMWin->pStart && pMWin->eStart==TK_FOLLOWING ){
assert( pMWin->eEnd==TK_FOLLOWING );
sqlite3VdbeAddOp3(v, OP_Subtract, regStart, regEnd, regEnd);
}
}
/* If this is "ROWS <expr1> FOLLOWING AND ROWS <expr2> FOLLOWING", do:
**
** regEnd = regEnd - regStart;
*/
if( pMWin->pEnd && pMWin->pStart && pMWin->eStart==TK_FOLLOWING ){
assert( pMWin->eEnd==TK_FOLLOWING );
sqlite3VdbeAddOp3(v, OP_Subtract, regStart, regEnd, regEnd);
}
/* Initialize the accumulator register for each window function to NULL */
for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum);
}
@@ -591,11 +658,7 @@ static void windowCodeDefaultStep(
}
/* Invoke step function for window functions */
for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
sqlite3VdbeAddOp3(v, OP_AggStep0, 0, reg+pWin->iArgCol, pWin->regAccum);
sqlite3VdbeAppendP4(v, pWin->pFunc, P4_FUNCDEF);
sqlite3VdbeChangeP5(v, (u8)pWin->nArg);
}
windowAggStep(pParse, pMWin, -1, 0, reg);
/* Buffer the current row in the ephemeral table. */
if( pMWin->nBufferCol>0 ){