Hello 2010/10/11 Greg Stark <gsst...@mit.edu>: > On Sun, Oct 10, 2010 at 2:16 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> It was pointed out upthread that while median isn't presently >> in the standard, Oracle defines it in terms of percentile_cont(0.5) >> which *is* in the standard. > > Uhmm, then why don't we implement that? We could provide median() as a > short-cut but percentile_cont() doesn't sound much harder to implement > than median() and more general.
The problem is in interface. The original patch did it, but I removed it. We cannot to unsure immutability of some parameters now. Can we enhance a AGGREGATE to allow some mark like IMMUTABLE parameter and probably we should to support ANSI syntax: PERCENTILE_CONT ( expression1 ) WITHIN GROUP ( ORDER BY expression2 [ ASC | DESC ] ) This syntax allows to divide a muttable and immutable parameters. Regards Pavel Stehule > > -- > greg > -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
