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Add implementation of window function ntile().

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FossilOrigin-Name: 3f093f608c6cc193aac77e7eafa8006c27a7776682d9d7b6e743710dff41ae42
This commit is contained in:
dan
2018-06-04 18:55:11 +00:00
parent 2b1287cf44
commit 6bc5c9e788
8 changed files with 1786 additions and 51 deletions
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82
src/window.c
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@@ -180,6 +180,69 @@ static void cume_distValueFunc(sqlite3_context *pCtx){
}
}
struct NtileCtx {
i64 nTotal; /* Total rows in partition */
i64 nParam; /* Parameter passed to ntile(N) */
i64 iRow; /* Current row */
};
/*
** Implementation of ntile(). This assumes that the window frame has
** been coerced to:
**
** ROWS UNBOUNDED PRECEDING AND CURRENT ROW
**
*/
static void ntileStepFunc(
sqlite3_context *pCtx,
int nArg,
sqlite3_value **apArg
){
struct NtileCtx *p;
assert( nArg==2 );
p = (struct NtileCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
if( p ){
if( p->nTotal==0 ){
p->nParam = sqlite3_value_int64(apArg[0]);
p->nTotal = sqlite3_value_int64(apArg[1]);
if( p->nParam<=0 ){
sqlite3_result_error(
pCtx, "argument of ntile must be a positive integer", -1
);
}
}
p->iRow++;
}
}
static void ntileInverseFunc(
sqlite3_context *pCtx,
int nArg,
sqlite3_value **apArg
){
}
static void ntileValueFunc(sqlite3_context *pCtx){
struct NtileCtx *p;
p = (struct NtileCtx*)sqlite3_aggregate_context(pCtx, sizeof(*p));
if( p && p->nParam>0 ){
int nSize = (p->nTotal / p->nParam);
if( nSize==0 ){
sqlite3_result_int64(pCtx, p->iRow);
}else{
i64 nLarge = p->nTotal - p->nParam*nSize;
i64 iSmall = nLarge*(nSize+1);
i64 iRow = p->iRow-1;
assert( (nLarge*(nSize+1) + (p->nParam-nLarge)*nSize)==p->nTotal );
if( iRow<iSmall ){
sqlite3_result_int64(pCtx, 1 + iRow/(nSize+1));
}else{
sqlite3_result_int64(pCtx, 1 + nLarge + (iRow-iSmall)/nSize);
}
}
}
}
static void nth_valueStepFunc(
sqlite3_context *pCtx,
int nArg,
@@ -211,6 +274,7 @@ void sqlite3WindowFunctions(void){
WINDOWFUNC(rank, 0, 0),
WINDOWFUNC(percent_rank, 0, SQLITE_FUNC_WINDOW_SIZE),
WINDOWFUNC(cume_dist, 0, SQLITE_FUNC_WINDOW_SIZE),
WINDOWFUNC(ntile, 1, SQLITE_FUNC_WINDOW_SIZE),
WINDOWFUNC(nth_value, 2, 0),
};
sqlite3InsertBuiltinFuncs(aWindowFuncs, ArraySize(aWindowFuncs));
@@ -219,7 +283,7 @@ void sqlite3WindowFunctions(void){
void sqlite3WindowUpdate(Parse *pParse, Window *pWin, FuncDef *pFunc){
if( pFunc->funcFlags & SQLITE_FUNC_WINDOW ){
sqlite3 *db = pParse->db;
if( pFunc->xSFunc==row_numberStepFunc ){
if( pFunc->xSFunc==row_numberStepFunc || pFunc->xSFunc==ntileStepFunc ){
sqlite3ExprDelete(db, pWin->pStart);
sqlite3ExprDelete(db, pWin->pEnd);
pWin->pStart = pWin->pEnd = 0;
@@ -561,16 +625,22 @@ static void windowAggStep(
int regArg;
int nArg = pWin->nArg;
if( flags & SQLITE_FUNC_WINDOW_SIZE ){
regArg = regPartSize;
nArg++;
}else if( csr>=0 ){
if( csr>=0 ){
int i;
for(i=0; i<pWin->nArg; i++){
sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol+i, reg+i);
}
regArg = reg;
if( flags & SQLITE_FUNC_WINDOW_SIZE ){
if( nArg==0 ){
regArg = regPartSize;
}else{
sqlite3VdbeAddOp2(v, OP_SCopy, regPartSize, reg+nArg);
}
nArg++;
}
}else{
assert( !(flags & SQLITE_FUNC_WINDOW_SIZE) );
regArg = reg + pWin->iArgCol;
}
@@ -902,7 +972,7 @@ static void windowCodeRowExprStep(
nArg = 0;
for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum);
nArg = MAX(nArg, pWin->nArg);
nArg = MAX(nArg, pWin->nArg+1);
}
regArg = pParse->nMem+1;
pParse->nMem += nArg;