一個用戶表,一個聊天記錄表,兩個表聯合查詢獲取聊天表中用戶最新的一條聊天數據
select c.content from sixin as c where c.tid = a.user_id order by ctime desc limit 0,1 ) as content, ( select c.status from sixin as c where c.tid = a.user_id order by ctime desc limit 0,1 ) as status from users as a, sixin as b where a.user_id = b.tid group by a.user_id