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@xxxxxxxxxxxxxxxxxxxxx> 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 -- http://preferans.de
