"Matthew Dennis" <mdennis(at)merfer(dot)net> writes:
> http://www.postgresql.org/docs/8.3/static/sql-createaggregate.html is for
> 8.3 where there were some changes to the number of arguments an aggregate
> could take. I believe it's also more descriptive documentation.
Also see the overview at
http://www.postgresql.org/docs/8.3/static/xaggr.html
regards, tom lane