if (version_compare(mysqli_get_server_info($xoopsDB->conn), '4.1.0', 'ge')):
            $sql = 'DELETE FROM ' . $this->db->prefix('bb_posts_text') . " WHERE (post_id NOT IN ( SELECT DISTINCT post_id FROM {$this->table}) )";
        else:
            // for 4.0+
            /* */