Hi, I'm trying to write a version of the MIN aggregate for values of RECORD type. I'm somewhat stuck on getting type information about the argument out, I can determine how many attributes it's got but I can't seem to do any better than that. Does anyone have any good pointers into the code for places to help me understand what's happening?
The reason for doing this is mainly because I think it'd be nicer to be doing things like: SELECT i, (MIN((j,k))).k FROM tbl GROUP BY i; instead of: SELECT DISTINCT ON (i) i, k FROM tbl ORDER BY i,j,k; Which as far as I can tell should produce identical results, except the first has cleaner semantics. It also allows you to combine MIN and MAX in the same query, giving the value of k for the smallest and largest j in this example--requiring two queries if it was done using the DISTINCT ON method. Sam -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
