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Add Oracle-compatible GREATEST and LEAST functions. Pavel Stehule

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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
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72
src/backend/parser/parse_expr.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.183 2005/06/04 20:56:13 momjian Exp $
* $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.184 2005/06/26 22:05:39 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -53,6 +53,7 @@ static Node *transformSubLink(ParseState *pstate, SubLink *sublink);
static Node *transformArrayExpr(ParseState *pstate, ArrayExpr *a);
static Node *transformRowExpr(ParseState *pstate, RowExpr *r);
static Node *transformCoalesceExpr(ParseState *pstate, CoalesceExpr *c);
static Node *transformMinMaxExpr(ParseState *pstate, MinMaxExpr *m);
static Node *transformBooleanTest(ParseState *pstate, BooleanTest *b);
static Node *transformColumnRef(ParseState *pstate, ColumnRef *cref);
static Node *transformWholeRowRef(ParseState *pstate, char *schemaname,
@@ -209,6 +210,10 @@ transformExpr(ParseState *pstate, Node *expr)
result = transformCoalesceExpr(pstate, (CoalesceExpr *) expr);
break;
case T_MinMaxExpr:
result = transformMinMaxExpr(pstate, (MinMaxExpr *) expr);
break;
case T_NullTest:
{
NullTest *n = (NullTest *) expr;
@@ -1229,6 +1234,44 @@ transformCoalesceExpr(ParseState *pstate, CoalesceExpr *c)
return (Node *) newc;
}
static Node *
transformMinMaxExpr(ParseState *pstate, MinMaxExpr *m)
{
MinMaxExpr *newm = makeNode(MinMaxExpr);
List *newargs = NIL;
List *newcoercedargs = NIL;
List *typeids = NIL;
ListCell *args;
newm->op = m->op;
foreach(args, m->args)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = transformExpr(pstate, e);
newargs = lappend(newargs, newe);
typeids = lappend_oid(typeids, exprType(newe));
}
newm->minmaxtype = select_common_type(typeids, "GREATEST/LEAST");
/* Convert arguments if necessary */
foreach(args, newargs)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = coerce_to_common_type(pstate, e,
newm->minmaxtype,
"GREATEST/LEAST");
newcoercedargs = lappend(newcoercedargs, newe);
}
newm->args = newcoercedargs;
return (Node *) newm;
}
static Node *
transformBooleanTest(ParseState *pstate, BooleanTest *b)
{
@@ -1503,6 +1546,9 @@ exprType(Node *expr)
case T_CoalesceExpr:
type = ((CoalesceExpr *) expr)->coalescetype;
break;
case T_MinMaxExpr:
type = ((MinMaxExpr *) expr)->minmaxtype;
break;
case T_NullIfExpr:
type = exprType((Node *) linitial(((NullIfExpr *) expr)->args));
break;
@@ -1637,6 +1683,30 @@ exprTypmod(Node *expr)
return typmod;
}
break;
case T_MinMaxExpr:
{
/*
* If all the alternatives agree on type/typmod, return
* that typmod, else use -1
*/
MinMaxExpr *mexpr = (MinMaxExpr *) expr;
Oid minmaxtype = mexpr->minmaxtype;
int32 typmod;
ListCell *arg;
typmod = exprTypmod((Node *) linitial(mexpr->args));
foreach(arg, mexpr->args)
{
Node *e = (Node *) lfirst(arg);
if (exprType(e) != minmaxtype)
return -1;
if (exprTypmod(e) != typmod)
return -1;
}
return typmod;
}
break;
case T_NullIfExpr:
{
NullIfExpr *nexpr = (NullIfExpr *) expr;