SELECT  m.chatid, m.userid, c.lastupdate FROM chat1.members m, chat1.chats c
WHERE  m.chatid IN
(SELECT chatid FROM chat1.members WHERE userid = ?i) AND c.id = m.chatid
AND m.userid <> ?i

SELECT lastvisit FROM chat1.members WHERE chatid = ?i AND userid = ?i

SELECT  m.chatid, m.userid, c.lastupdate FROM chat1.members m, chat1.chats c
WHERE  m.chatid IN (SELECT chatid FROM chat1.members WHERE userid = ?i) AND c.id = m.chatid
AND m.userid <> ?i
UNION SELECT lastvisit FROM chat1.members WHERE chatid = m.chatid AND userid = ?i