$sql = "SELECT DISTINCT n.nid, n.title, " .
               " (SELECT max(c.timestamp) FROM comments c WHERE c.nid = n.nid) timestamp " .
               "FROM {forum} f " .
               "LEFT JOIN {node} n ON f.nid = n.nid " .
               "LEFT JOIN {comments} c ON f.nid = c.nid " .
               "LEFT JOIN {term_node} tn ON tn.nid = n.nid " .
               "LEFT JOIN {og_ancestry} oga ON oga.nid = n.nid " .
               "LEFT JOIN {og} ON oga.group_nid = og.nid " .
               "WHERE tn.tid = %d " .
               "AND ((ou.uid = $user->uid AND na.realm = 'og_public') OR na.realm = 'og_public')".
               "AND og.private = '0' " .
               "AND og.directory = '1' " .
               "ORDER BY timestamp DESC, n.created DESC " .
               "LIMIT 4";