Re: BUG #5490: Using distinct for select list causes insert of timestamp string literal to fail

I know it's not what you want (Pg behaving how you expect out of the
box) but creating implicit casts to the desired types will resolve your
immediate issue. You still have to run some Pg-specific code, but it can
be restricted to your DDL where there's (presumably) already plenty.

See:

http://www.depesz.com/index.php/2008/05/05/error-operator-does-not-exist-integer-text-how-to-fix-it/

http://petereisentraut.blogspot.com/2008/03/readding-implicit-casts-in-postgresql.html

http://wiki.postgresql.org/images/d/d1/Pg83-implicit-casts.sql

--
Craig Ringer