From 8e8854daa2b4b3ef9e3fc1a56c79608a70018058 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 31 Dec 2008 00:08:39 +0000
Subject: 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.

---
 src/backend/utils/adt/ruleutils.c | 37 +++++++++++++++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

(limited to 'src/backend/utils/adt/ruleutils.c')

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 969977cea51..4a44b733cf3 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.291 2008/12/28 18:53:59 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.292 2008/12/31 00:08:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2903,7 +2903,7 @@ get_rule_windowspec(WindowClause *wc, List *targetList,
 		appendStringInfoString(buf, quote_identifier(wc->refname));
 		needspace = true;
 	}
-	/* partitions are always inherited, so only print if no refname */
+	/* partition clauses are always inherited, so only print if no refname */
 	if (wc->partitionClause && !wc->refname)
 	{
 		if (needspace)
@@ -2921,6 +2921,7 @@ get_rule_windowspec(WindowClause *wc, List *targetList,
 		}
 		needspace = true;
 	}
+	/* print ordering clause only if not inherited */
 	if (wc->orderClause && !wc->copiedOrder)
 	{
 		if (needspace)
@@ -2929,6 +2930,38 @@ get_rule_windowspec(WindowClause *wc, List *targetList,
 		get_rule_orderby(wc->orderClause, targetList, false, context);
 		needspace = true;
 	}
+	/* framing clause is never inherited, so print unless it's default */
+	if (wc->frameOptions & FRAMEOPTION_NONDEFAULT)
+	{
+		if (needspace)
+			appendStringInfoChar(buf, ' ');
+		if (wc->frameOptions & FRAMEOPTION_RANGE)
+			appendStringInfoString(buf, "RANGE ");
+		else if (wc->frameOptions & FRAMEOPTION_ROWS)
+			appendStringInfoString(buf, "ROWS ");
+		else
+			Assert(false);
+		if (wc->frameOptions & FRAMEOPTION_BETWEEN)
+			appendStringInfoString(buf, "BETWEEN ");
+		if (wc->frameOptions & FRAMEOPTION_START_UNBOUNDED_PRECEDING)
+			appendStringInfoString(buf, "UNBOUNDED PRECEDING ");
+		else if (wc->frameOptions & FRAMEOPTION_START_CURRENT_ROW)
+			appendStringInfoString(buf, "CURRENT ROW ");
+		else
+			Assert(false);
+		if (wc->frameOptions & FRAMEOPTION_BETWEEN)
+		{
+			appendStringInfoString(buf, "AND ");
+			if (wc->frameOptions & FRAMEOPTION_END_UNBOUNDED_FOLLOWING)
+				appendStringInfoString(buf, "UNBOUNDED FOLLOWING ");
+			else if (wc->frameOptions & FRAMEOPTION_END_CURRENT_ROW)
+				appendStringInfoString(buf, "CURRENT ROW ");
+			else
+				Assert(false);
+		}
+		/* we will now have a trailing space; remove it */
+		buf->len--;
+	}
 	appendStringInfoChar(buf, ')');
 }
 
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