Implement the FILTER clause for aggregate function calls.

This is SQL-standard with a few extensions, namely support for
subqueries and outer references in clause expressions.

catversion bump due to change in Aggref and WindowFunc.

David Fetter, reviewed by Dean Rasheed.

1 files changed, 14 insertions, 0 deletions

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index cf9ce3f3a15..976bc98e375 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -7424,6 +7424,13 @@ get_agg_expr(Aggref *aggref, deparse_context *context)
 		appendStringInfoString(buf, " ORDER BY ");
 		get_rule_orderby(aggref->aggorder, aggref->args, false, context);
 	}
+
+	if (aggref->aggfilter != NULL)
+	{
+		appendStringInfoString(buf, ") FILTER (WHERE ");
+		get_rule_expr((Node *) aggref->aggfilter, context, false);
+	}
+
 	appendStringInfoChar(buf, ')');
 }
 
@@ -7461,6 +7468,13 @@ get_windowfunc_expr(WindowFunc *wfunc, deparse_context *context)
 		appendStringInfoChar(buf, '*');
 	else
 		get_rule_expr((Node *) wfunc->args, context, true);
+
+	if (wfunc->aggfilter != NULL)
+	{
+		appendStringInfoString(buf, ") FILTER (WHERE ");
+		get_rule_expr((Node *) wfunc->aggfilter, context, false);
+	}
+
 	appendStringInfoString(buf, ") OVER ");
 
 	foreach(l, context->windowClause)