This is what I did:
	create table a (a int, a1 char(8));
	create table b (b int);
	insert into a values (1, 'one');
	insert into a values (NULL, 'null');

and this is what I got from Informix:
> select * from a where a not in (select * from b);
          a a1
          1 one
            null
2 row(s) retrieved.
>  select * from a where not (a in (select * from b));
          a a1
          1 one
            null
2 row(s) retrieved.
> select * from a where not a in (select * from b);
          a a1
          1 one
            null
2 row(s) retrieved.
> select * from a where a<>(select * from b);
          a a1
No rows found.
> select * from a where a=(select * from b);
          a a1
No rows found.

Andreas

Wed, 18 Feb 1998 18:32:40 +0100
Zeugswetter Andreas SARZ <Andreas.Zeugswetter@telecom.at>
Re: [HACKERS] Subselects and NOTs