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

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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.
This commit is contained in:
Tom Lane
2008-12-31 00:08:39 +00:00
parent 0fb9be7acf
commit 8e8854daa2
24 changed files with 757 additions and 307 deletions
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37
src/backend/utils/adt/ruleutils.c
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@@ -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, ')');
}