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On second thought, expression_tree_walker should handle bare

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SubLink nodes after all ...
This commit is contained in:
Tom Lane
1999-06-21 01:18:02 +00:00
parent db4a6a2618
commit 974bdd94f9
2 changed files with 24 additions and 32 deletions
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36
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 1.22 1999/06/19 03:48:31 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/parser/parse_agg.c,v 1.23 1999/06/21 01:18:02 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -43,9 +43,7 @@ static bool exprIsAggOrGroupCol_walker(Node *node, List *groupClauses);
* Returns true if any aggregate found.
*
* NOTE: we assume that the given clause has been transformed suitably for
* parser output. This means we can use the planner's expression_tree_walker,
* except that we have to process SubLink nodes specially, since they haven't
* been turned into SubPlan nodes yet.
* parser output. This means we can use the planner's expression_tree_walker.
*/
static bool
contain_agg_clause(Node *clause)
@ -60,12 +58,6 @@ contain_agg_clause_walker(Node *node, void *context)
return false;
if (IsA(node, Aggref))
return true; /* abort the tree traversal and return true */
if (IsA(node, SubLink))
{
/* Examine the lefthand side, but not the oper list nor the subquery */
SubLink *sublink = (SubLink *) node;
return contain_agg_clause_walker((Node *) sublink->lefthand, context);
}
return expression_tree_walker(node, contain_agg_clause_walker, context);
}
@ -75,16 +67,15 @@ contain_agg_clause_walker(Node *node, void *context)
* other than within the arguments of aggregate functions.
*
* NOTE: we assume that the given clause has been transformed suitably for
* parser output. This means we can use the planner's expression_tree_walker,
* except that we have to process SubLink nodes specially, since they haven't
* been turned into SubPlan nodes yet.
* parser output. This means we can use the planner's expression_tree_walker.
*
* NOTE: in the case of a SubLink, we do not descend into the subquery. This
* means we will fail to detect ungrouped columns that appear as outer-level
* variables within a subquery. That seems unreasonably hard to handle here.
* Instead, we expect the planner to check for ungrouped columns after it's
* found all the outer-level references inside the subquery and converted
* them into a list of parameters for the subquery.
* NOTE: in the case of a SubLink, expression_tree_walker does not descend
* into the subquery. This means we will fail to detect ungrouped columns
* that appear as outer-level variables within a subquery. That case seems
* unreasonably hard to handle here. Instead, we expect the planner to check
* for ungrouped columns after it's found all the outer-level references
* inside the subquery and converted them into a list of parameters for the
* subquery.
*/
static bool
exprIsAggOrGroupCol(Node *expr, List *groupClauses)
@ -128,13 +119,6 @@ exprIsAggOrGroupCol_walker(Node *node, List *groupClauses)
return false; /* outer-level Var is acceptable */
}
/* Otherwise, recurse. */
if (IsA(node, SubLink))
{
/* Examine the lefthand side, but not the oper list nor the subquery */
SubLink *sublink = (SubLink *) node;
return exprIsAggOrGroupCol_walker((Node *) sublink->lefthand,
groupClauses);
}
return expression_tree_walker(node, exprIsAggOrGroupCol_walker,
(void *) groupClauses);
}