Optimisation d'une sous-requête SQL

SELECT a.id,a.forum_name,a.forum_desc,a.forum_lock,
(SELECT COUNT(*) FROM forums_msg WHERE cat=a.id) AS nbr_msg,
(SELECT login FROM members WHERE id=auth LIMIT 1) AS login
(SELECT auth FROM forums_msg WHERE cat=a.id ORDER BY id DESC LIMIT 1) AS auth,
(SELECT reply FROM forums_msg WHERE cat=a.id ORDER BY id DESC LIMIT 1) AS reply,
(SELECT date FROM forums_msg WHERE cat=a.id ORDER BY id DESC LIMIT 1) AS last_date
FROM forums AS a WHERE a.forum_cat='1' ORDER BY a.forum_name ASC;

(SELECT auth FROM forums_msg WHERE cat=a.id ORDER BY id DESC LIMIT 1) AS auth,
(SELECT reply FROM forums_msg WHERE cat=a.id ORDER BY id DESC LIMIT 1) AS reply,
(SELECT date FROM forums_msg WHERE cat=a.id ORDER BY id DESC LIMIT 1) AS last_date

SELECT a.id,a.forum_name,a.forum_desc,a.forum_lock,
login, COUNT(*) as nbr_msg, auth,reply, last_date
FROM forums AS a WHERE a.forum_cat='1' ORDER BY a.forum_name ASC
INNER JOIN forums_msg ON cat = a.id
INNER JOIN members  ON id=auth
GROUP BY a.id,a.forum_name,a.forum_desc,a.forum_lock,
login,auth,reply, last_date