set @csum := 0;
set @prevUser := 0;
SELECT id, points, order,
@csum := IF( @prevUser=`user_id`, @csum + points , points ) AS total,
@prevUser := `user_id`
FROM `table`
ORDER BY `user_id`, order
Omezeni: ORDER BY musi byt jak, prirazeni prevUser musi byt az po csum