On Friday 21 September 2018 16:11:17 Pavel Stehule wrote:
> maybe some value emp_u_id from employees is NULL. It is expected behave
>
> http://blog.9minutesnooze.com/sql-not-in-subquery-null/
>
> Regards
>
> Pavel
Thanks for this.
As I said in my description, some values will be NULL. I just thought that
these would not be included in the select. I did not think that it would stop
the subselect from working
users=# select count(u_id) from users where u_id not in (select distinct
emp_u_id from employees where emp_u_id is not null);
count
-------
393
(1 row)
users=#