Jim Nasby <Jim.Nasby@BlueTreble.com> writes:
> Is there any reason we couldn't/shouldn't support IS DISTINCT in
> subquery_Op? (Or really, just add support to ANY()/ALL()/(SELECT ...)?)
It's not an operator (in the sense of something with a pg_operator OID),
which means this would be quite a bit less than trivial as far as internal
representation/implementation goes. I'm not sure if there would be
grammar issues, either.
regards, tom lane