diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/func.sgml | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 3f627dc885f..ff7545de156 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -13102,8 +13102,9 @@ SELECT count(*) FROM sometable; SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab; ]]></screen> - But this syntax is not allowed in the SQL standard, and is - not portable to other database systems. + Beware that this approach can fail if the outer query level contains + additional processing, such as a join, because that might cause the + subquery's output to be reordered before the aggregate is computed. </para> <para> |