database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-27 23:21:58 +03:00
Code Activity

Add Oracle-compatible GREATEST and LEAST functions. Pavel Stehule

Browse Source
This commit is contained in:
Tom Lane
2005-06-26 22:05:42 +00:00
parent d395aecffa
commit 943b396245
17 changed files with 409 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files

92
src/backend/executor/execQual.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.179 2005/05/12 20:41:56 tgl Exp $
* $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.180 2005/06/26 22:05:36 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -105,6 +105,9 @@ static Datum ExecEvalRow(RowExprState *rstate,
static Datum ExecEvalCoalesce(CoalesceExprState *coalesceExpr,
ExprContext *econtext,
bool *isNull, ExprDoneCond *isDone);
static Datum ExecEvalMinMax(MinMaxExprState *minmaxExpr,
ExprContext *econtext,
bool *isNull, ExprDoneCond *isDone);
static Datum ExecEvalNullIf(FuncExprState *nullIfExpr,
ExprContext *econtext,
bool *isNull, ExprDoneCond *isDone);
@ -2247,6 +2250,63 @@ ExecEvalCoalesce(CoalesceExprState *coalesceExpr, ExprContext *econtext,
return (Datum) 0;
}
/* ----------------------------------------------------------------
* ExecEvalMinMax
* ----------------------------------------------------------------
*/
static Datum
ExecEvalMinMax(MinMaxExprState *minmaxExpr, ExprContext *econtext,
bool *isNull, ExprDoneCond *isDone)
{
Datum result = (Datum) 0;
MinMaxOp op = ((MinMaxExpr *) minmaxExpr->xprstate.expr)->op;
FunctionCallInfoData locfcinfo;
ListCell *arg;
if (isDone)
*isDone = ExprSingleResult;
*isNull = true; /* until we get a result */
InitFunctionCallInfoData(locfcinfo, &minmaxExpr->cfunc, 2, NULL, NULL);
locfcinfo.argnull[0] = false;
locfcinfo.argnull[1] = false;
foreach(arg, minmaxExpr->args)
{
ExprState *e = (ExprState *) lfirst(arg);
Datum value;
bool valueIsNull;
int32 cmpresult;
value = ExecEvalExpr(e, econtext, &valueIsNull, NULL);
if (valueIsNull)
continue; /* ignore NULL inputs */
if (*isNull)
{
/* first nonnull input, adopt value */
result = value;
*isNull = false;
}
else
{
/* apply comparison function */
locfcinfo.arg[0] = result;
locfcinfo.arg[1] = value;
locfcinfo.isnull = false;
cmpresult = DatumGetInt32(FunctionCallInvoke(&locfcinfo));
if (locfcinfo.isnull) /* probably should not happen */
continue;
if (cmpresult > 0 && op == IS_LEAST)
result = value;
else if (cmpresult < 0 && op == IS_GREATEST)
result = value;
}
}
return result;
}
/* ----------------------------------------------------------------
* ExecEvalNullIf
*
@ -3206,6 +3266,36 @@ ExecInitExpr(Expr *node, PlanState *parent)
state = (ExprState *) cstate;
}
break;
case T_MinMaxExpr:
{
MinMaxExpr *minmaxexpr = (MinMaxExpr *) node;
MinMaxExprState *mstate = makeNode(MinMaxExprState);
List *outlist = NIL;
ListCell *l;
TypeCacheEntry *typentry;
mstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecEvalMinMax;
foreach(l, minmaxexpr->args)
{
Expr *e = (Expr *) lfirst(l);
ExprState *estate;
estate = ExecInitExpr(e, parent);
outlist = lappend(outlist, estate);
}
mstate->args = outlist;
/* Look up the btree comparison function for the datatype */
typentry = lookup_type_cache(minmaxexpr->minmaxtype,
TYPECACHE_CMP_PROC);
if (!OidIsValid(typentry->cmp_proc))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("could not identify a comparison function for type %s",
format_type_be(minmaxexpr->minmaxtype))));
fmgr_info(typentry->cmp_proc, &(mstate->cfunc));
state = (ExprState *) mstate;
}
break;
case T_NullIfExpr:
{
NullIfExpr *nullifexpr = (NullIfExpr *) node;