[RESOLVED] mySQL: Selecting items NOT in another list

[infected_toe]

tables:

users
userid
username
userfname
userlname
etc

usergroups
groupid
groupname

usergroup_users
userid
groupid

Users can be members of multiple groups.

Page should look like:

Group page: $groupid - $groupname

$userfname $userlname
$userfname $userlname
$userfname $userlname
etc.

This is how I populate the list of who is in the group:
SELECT * FROM users, usergroup_users WHERE (users.userid=usergroup_users.userid) AND groupid='$groupid';

xxxxxxxxxxxxxxxx

My problem is a query for: Dropdown box for users who aren't member of the current group with an Add to Group button.

I tried:
SELECT * FROM users, usergroup_users WHERE (users.userid=usergroup_users.userid) AND groupid!='$groupid';

... but if a user is a member of another group, he will show up again.

Not very good at sql statements. I need some help here.

[nemonoman]

SELECT * FROM users WHERE users.userid NOT IN (SELECT users.userid FROM users, usergroup_users WHERE (users.userid=usergroup_users.userid) AND groupid='$groupid')

[infected_toe]

Exactly what I was looking for. THANKS!