Question

I am trying to select all users from the user database which are NOT subscribed to a particular mail list. The inner query finds the user if it is a member of the list and the outer query selects all users where the inner result is zero rows.

SELECT u.userid, u.username, u.mail, u.name, 
    u.lastname, u.starting_year, u.userid AS UIDD 
FROM userdb.users AS u 
WHERE (SELECT COUNT(*) FROM maildb.lists AS l, 
        maildb.list_subscriptions AS s, userdb.users AS u 
    WHERE u.userid = UIDD 
    AND l.listid = '$LIST_ID_TO_LOOKUP' 
    AND s.userid = u.userid 
    AND s.listid = l.listid) = 0 
ORDER BY u.starting_year DESC, u.lastname, u.name;

This worked just fine until I moved to a new server and updated many components, including MySQL.

Now I get an error when running this query:

#1054 – Unknown column ‘UIDD’ in ‘where clause’

Could this be a problem with an old syntax that is now depricated? I am now running MySQL 5.5.24.

Answer 1

Something like this, SELECT .. WHERE userid NOT IN (subquery)

SELECT 
 u.userid, 
 u.username, 
 u.mail, 
 u.name, 
 u.lastname,
 u.starting_year, 
 u.userid AS UIDD 
FROM 
 userdb.users AS u 
WHERE 
 u.userid NOT IN (
    SELECT 
      u.userid 
    FROM 
      maildb.lists AS l, 
      maildb.list_subscriptions AS s, 
      userdb.users AS u 
    WHERE 
      u.userid = u.userid 
      AND l.listid = '$LIST_ID_TO_LOOKUP' 
      AND s.userid = u.userid 
      AND s.listid = l.listid
    ) 
ORDER BY 
 u.starting_year DESC, u.lastname, u.name;