Re: select * from users where user_id NOT in (select

Hello,

thank you and sorry for asking a FAQ.
I've fixed my problem now by:

select user_id, username from phpbb_users where user_id not in
(select ban_userid from phpbb_banlist where ban_userid is not null);

but still your explanation feels illogical
to me even though I know you're right...

On 8/18/06, Stephan Szabo <sszabo@megazone.bigpanda.com> wrote:
> When the subselect returns
> NULL for at least one row, you fall into this sort of case.
>
> x NOT IN (...) is equivalent to NOT(x IN (...)) which is
> NOT(x = ANY (...))
>
> x = ANY (...) is basically defined as
>  True if x = y is true for some y in the subselect
>  False if x = y is false for all y in the subselect
>  Unknown otherwise
>
> Since x = NULL is unknown and not true or false, you fall into the last
> case with your query and data.
>

Regards
Alex

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