Your query isn't a condition of any sort. You're just querying for a value and aren't conditioning it. Looks like there's also an extra bracket. The below should work.
Code:
( ( SELECT COUNT(*) FROM `#__groupjive_users` AS gj WHERE gj.`group` = '23' AND gj.`user_id` = u.`id` AND gj.`status` IN ( 1, 2, 3, 4 ) ) > 0 )