Re: select where not in () fails

pá 21. 9. 2018 v 17:20 odesílatel Gary Stainburn <
gary(dot)stainburn(at)ringways(dot)co(dot)uk> napsal:

> 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
>

It is common issue. But it has sense.

Regards

Pavel

>
> 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=#
>