>>>>> "Heikki" == Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> writes:
>> No artificial restrictions are imposed on what syntactical>> combinations are allowed. However, ORDER BY is not
allowedwith>> aggregates used as window functions (as per the existing>> restriction on DISTINCT).
Heikki> How is this different from window functions?
Window functions return a row for each row of input, aggregates don't.
The reason I didn't tackle the case of aggregate functions used as
window functions is that the spec allows constructs like this:
array_agg(a order by b) over (order by c)
which can't be represented using the aggregate-as-window-function
mechanism as it currently stands, since you'd have to re-sort the
window each time.
--
Andrew (irc:RhodiumToad)
