[RESOLVED] MySQL Join - selecting rows from table A which doesn't exist in table B

[lpa]

This is a query which whows friends who are online by selecting rows which exist in tables
friends, usertable, session

$result = mysql_query("SELECT 
friends.id, friends.nick, usertable.photo 
FROM friends use index (owner) 
join usertable on friends.friendid = usertable.id 
join session on friends.friendid = session.user 
WHERE friends.owner='$id' and friends.approved='1' 
order by friends.nick limit $start, $step") or die(mysql_error());

But now I need to display friends who are not online (don't exist in table session)
Is it possible to use Join to select rows which exist in tables
friends, usertable
but doesn't exist in table
session ?

Thanks.

[bradgrafelman]

You could do a subquery, e.g.:

WHERE id NOT IN (SELECT user FROM session)

[lpa]

thank you