>>>>> "Heikki" == Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> writes:
>> Herewith a patch to implement agg(foo ORDER BY bar) with or>> without DISTINCT, etc.
Heikki> What does that mean? Aggregate functions are supposed to beHeikki> commutative, right?
The SQL spec defines two non-commutative aggregates that we implement:
array_agg(x ORDER BY ...)
xmlagg(x ORDER BY ...)
In addition, of course, we allow user-defined aggregates, which are
perfectly free to be non-commutative.
--
Andrew (irc:RhodiumToad)
