$sql = "SELECT t.topic_title, t.topic_id, u.username FROM topics as t, " .
                   "posts as p, users as u INNER JOIN forums as f ON ".
                   "f.forum_id = '" . $subforum . "' OR f.forum_parent = '" . $subforum_parent .
                   "' WHERE p.post_time >= '". $starttime .
                   "' AND p.post_time < '" . $endtime . "' AND p.topic_id = t.topic_id AND " .
                   "p.poster_id = t.topic_poster and u.user_id = t.topic_poster AND " .
                   "p.forum_id = f.forum_id " .
                   "GROUP BY t.topic_id ORDER BY t.topic_title ASC";