On Thu, Aug 6, 2009 at 1:38 PM, Jeff Davis<pgsql@xxxxxxxxxxx> wrote: > On Thu, 2009-08-06 at 13:15 -0400, Merlin Moncure wrote: >> in 8.4 you can (and should) do: >> WHERE old = new > > I couldn't get that to work in a rule. it should, maybe try old::foo = new::foo >> IF NEW != OLD THEN -- 8.4 syntax > > Does this work correctly in the case of NULLs? It looks like it does, > but that seems strange, because ROW(1, NULL) = ROW(1, NULL) evaluates to > NULL. Where is this documented? If you think that's weird, check out: postgres=# select (50, 0)::foo > (50, null)::foo; ?column? ---------- f (1 row) postgres=# select (50, 0)::foo < (50, null)::foo; ?column? ---------- t (1 row) I think maybe Pavel is right and is distinct from is safer, but I'd argue against any change that disallowed comparisons of composites with nulls in them. merlin -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
