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| author | Noah Misch <noah@leadboat.com> | 2013-07-16 20:15:36 -0400 |
|---|---|---|
| committer | Noah Misch <noah@leadboat.com> | 2013-07-16 20:15:36 -0400 |
| commit | b560ec1b0d7b910ce13edc51ffaafaca72136e3b (patch) | |
| tree | ae5d80c94681788fd214efe6d61425089850781e /doc/src/sgml/ref | |
| parent | 7a8e9f298e7b8158296e1ea72ca8987323c10edf (diff) | |
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.
Diffstat (limited to 'doc/src/sgml/ref')
| -rw-r--r-- | doc/src/sgml/ref/select.sgml | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml index 68309ba94da..b0cec1421ca 100644 --- a/doc/src/sgml/ref/select.sgml +++ b/doc/src/sgml/ref/select.sgml @@ -598,6 +598,11 @@ GROUP BY <replaceable class="parameter">expression</replaceable> [, ...] making up each group, producing a separate value for each group (whereas without <literal>GROUP BY</literal>, an aggregate produces a single value computed across all the selected rows). + The set of rows fed to the aggregate function can be further filtered by + attaching a <literal>FILTER</literal> clause to the aggregate function + call; see <xref linkend="syntax-aggregates"> for more information. When + a <literal>FILTER</literal> clause is present, only those rows matching it + are included. When <literal>GROUP BY</literal> is present, it is not valid for the <command>SELECT</command> list expressions to refer to ungrouped columns except within aggregate functions or if the |