SELECT
  T.id AS tid,
  T.title,
  P.id AS pid,
  P.time, 
  U.username,
  U.id as uid,
  (
    SELECT COUNT(id) 
    FROM tv_forum_readposts 
    WHERE userid=U.id 
      AND threadid=T.id 
      AND lastpostread=P.id
  ) AS `read`
  FROM tv_forum_threads T 
  LEFT JOIN tv_forum_posts P 
    ON T.last_post = P.id 
  RIGHT JOIN tv_users U 
    ON P.userid = U.id 
  WHERE T.category = 1 
  ORDER BY 
    P.time DESC,
    P.id DESC
  LIMIT 1