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Fix for count(*), aggs with views and multiple tables and sum(3).

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This commit is contained in:
Bruce Momjian
1998-01-04 04:31:43 +00:00
parent c629d3b9d6
commit 4b05912f0b
15 changed files with 215 additions and 97 deletions
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84
src/backend/parser/parse_agg.c
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@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/parser/parse_agg.c,v 1.4 1997/12/22 05:42:19 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/parser/parse_agg.c,v 1.5 1998/01/04 04:31:14 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -18,14 +18,17 @@
#include "postgres.h"
#include "access/heapam.h"
#include "catalog/pg_aggregate.h"
#include "catalog/pg_type.h"
#include "nodes/nodeFuncs.h"
#include "nodes/primnodes.h"
#include "nodes/relation.h"
#include "optimizer/clauses.h"
#include "parser/parse_agg.h"
#include "parser/parse_expr.h"
#include "parser/parse_node.h"
#include "parser/parse_target.h"
#include "utils/syscache.h"
#include "utils/lsyscache.h"
static bool contain_agg_clause(Node *clause);
static bool exprIsAggOrGroupCol(Node *expr, List *groupClause);
@ -276,7 +279,8 @@ parseCheckAggregates(ParseState *pstate, Query *qry)
Aggreg *
ParseAgg(char *aggname, Oid basetype, Node *target)
ParseAgg(ParseState *pstate, char *aggname, Oid basetype,
List *target, int precedence)
{
Oid fintype;
Oid vartype;
@ -284,7 +288,8 @@ ParseAgg(char *aggname, Oid basetype, Node *target)
Form_pg_aggregate aggform;
Aggreg *aggreg;
HeapTuple theAggTuple;
bool usenulls = false;
theAggTuple = SearchSysCacheTuple(AGGNAME, PointerGetDatum(aggname),
ObjectIdGetDatum(basetype),
0, 0);
@ -293,21 +298,78 @@ ParseAgg(char *aggname, Oid basetype, Node *target)
elog(WARN, "aggregate %s does not exist", aggname);
}
/*
* We do a major hack for count(*) here.
*
* Count(*) poses several problems. First, we need a field that is
* guaranteed to be in the range table, and unique. Using a constant
* causes the optimizer to properly remove the aggragate from any
* elements of the query.
* Using just 'oid', which can not be null, in the parser fails on:
*
* select count(*) from tab1, tab2 -- oid is not unique
* select count(*) from viewtable -- views don't have real oids
*
* So, for an aggregate with parameter '*', we use the first valid
* range table entry, and pick the first column from the table.
* We set a flag to count nulls, because we could have nulls in
* that column.
*/
if (nodeTag(lfirst(target)) == T_Const)
{
Const *con = (Const *)lfirst(target);
if (con->consttype == UNKNOWNOID && VARSIZE(con->constvalue) == VARHDRSZ)
{
Attr *attr = makeNode(Attr);
List *rtable, *rlist;
RangeTblEntry *first_valid_rte;
Assert(lnext(target) == NULL);
if (pstate->p_is_rule)
rtable = lnext(lnext(pstate->p_rtable));
else
rtable = pstate->p_rtable;
first_valid_rte = NULL;
foreach(rlist, rtable)
{
RangeTblEntry *rte = lfirst(rlist);
/* only entries on outer(non-function?) scope */
if (!rte->inFromCl && rte != pstate->p_target_rangetblentry)
continue;
first_valid_rte =rte;
break;
}
if (first_valid_rte == NULL)
elog(WARN, "Can't find column to do aggregate(*) on.");
attr->relname = first_valid_rte->refname;
attr->attrs = lcons(makeString(
get_attname(first_valid_rte->relid,1)),NIL);
lfirst(target) = transformExpr(pstate, (Node *) attr, precedence);
usenulls = true;
}
}
aggform = (Form_pg_aggregate) GETSTRUCT(theAggTuple);
fintype = aggform->aggfinaltype;
xfn1 = aggform->aggtransfn1;
if (nodeTag(target) != T_Var && nodeTag(target) != T_Expr)
elog(WARN, "parser: aggregate can only be applied on an attribute or expression");
/* only aggregates with transfn1 need a base type */
if (OidIsValid(xfn1))
{
basetype = aggform->aggbasetype;
if (nodeTag(target) == T_Var)
vartype = ((Var *) target)->vartype;
if (nodeTag(lfirst(target)) == T_Var)
vartype = ((Var *) lfirst(target))->vartype;
else
vartype = ((Expr *) target)->typeOid;
vartype = ((Expr *) lfirst(target))->typeOid;
if (basetype != vartype)
{
@ -327,7 +389,9 @@ ParseAgg(char *aggname, Oid basetype, Node *target)
aggreg->basetype = aggform->aggbasetype;
aggreg->aggtype = fintype;
aggreg->target = target;
aggreg->target = lfirst(target);
if (usenulls)
aggreg->usenulls = true;
return aggreg;
}