2009/12/16 Thom Brown <thombr...@gmail.com>: > 2009/12/15 Pavel Stehule <pavel.steh...@gmail.com> >> >> Hello >> >> I am looking on new feature - ORDER clause in aggregate, and I thing, >> so we are able to effectively implement some non standard, but well >> known aggregates. >> >> a) function median - it is relative frequent request - with usually >> slow implementation >> >> b) function listagg (it is analogy of group_concat from MySQL) - it >> should simplify report generating and some other >> >> What is your opinion? Do you like to see these functions in core? >> >> > > I'm probably missing the point here, but when I originally saw MySQL's > group_concat function, I found it odd that it featured ordering > functionality. Shouldn't the order by determined by the query itself? > Otherwise it's almost as if its separating the relationship between the > result column and the resultset. >
Aggregates as group_concat or listagg are not typical SQL aggregates. With these aggregates we are able to do some reports on SQL level without stored procedures. What I know, order is determined only for non hash aggregates - and you cannot specify method of aggregation, so possibility to specify ORDER is important. But this feature isn't related to this "proposal". It was commited yesterday - so you can look on discussion about this feature. Regards Pavel Stehuke > Thom > > -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers