Re: BUG #6701: IS NOT NULL doesn't work on complex composites

rikard(dot)pavelic(at)zg(dot)htnet(dot)hr writes:
> create type t AS (i int);
> create type complex as (t t, i int);
> create table bad(i int, c complex);

> insert into bad values(1, null);
> insert into bad values(1, ROW(null, 2));
> insert into bad values(1, ROW(ROW(1), 2));

> select * from bad;
> select * from bad where c is null;

> --This doesn't work as expected
> select * from bad where c is not null;

What do you consider to be "expected"? Have you read the documentation
where it points out that IS NULL and IS NOT NULL are not inverses for
composite values?
http://www.postgresql.org/docs/9.1/static/functions-comparison.html

(I'm not that thrilled with this behavior either, but it is per SQL
standard AFAICT.)

regards, tom lane