Why can I not get Desc order for total\_time\_driven\_at\_this\_trip?

```
    SELECT DISTINCT (`name`), 
           MAX( `total_time_driven_at_this_trip` ) as trip
     FROM `users` 
LEFT JOIN `trip_nsws` ON users.id = trip_nsws.user_id
 GROUP BY `user_id`
 ORDER BY `total_time_driven_at_this_trip` DESC
    LIMIT 0 , 30

```