Add some basic support for window frame clauses to the window-functions

patch.  This includes the ability to force the frame to cover the whole
partition, and the ability to make the frame end exactly on the current row
rather than its last ORDER BY peer.  Supporting any more of the full SQL
frame-clause syntax will require nontrivial hacking on the window aggregate
code, so it'll have to wait for 8.5 or beyond.

1 files changed, 3 insertions, 2 deletions

diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index df30361f0a5..247d54d8782 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_clause.c,v 1.182 2008/12/28 18:53:58 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_clause.c,v 1.183 2008/12/31 00:08:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1554,7 +1554,7 @@ transformWindowDefinitions(ParseState *pstate,
 		 * Per spec, a windowdef that references a previous one copies the
 		 * previous partition clause (and mustn't specify its own).  It can
 		 * specify its own ordering clause. but only if the previous one
-		 * had none.
+		 * had none.  It always specifies its own framing clause.
 		 */
 		if (refwc)
 		{
@@ -1592,6 +1592,7 @@ transformWindowDefinitions(ParseState *pstate,
 			wc->orderClause = orderClause;
 			wc->copiedOrder = false;
 		}
+		wc->frameOptions = windef->frameOptions;
 		wc->winref = winref;
 
 		result = lappend(result, wc);