php mysql Group By to get latest record, not first record

Question

The Table:

(`post_id`, `forum_id`, `topic_id`, `post_time`) 
(79, 8, 4, \'2012-11-19 06:58:08\');
(80, 3, 3, \'2012-11-19 06:58:42\'),
(81, 9, 9, \'2012-11-1         


        

Answer 1

This will also work fine for you.

SELECT *
FROM (
  SELECT post_id, forum_id, topic_id FROM posts
  ORDER BY post_time DESC
  LIMIT 5
) customeTable
GROUP BY topic_id