删除行以在Oracle表中每个组具有最多x行

假设表中的组合

(person_id, car_id)

delete from car_assignment where (person_id, car_id)         in (select person_id, car_id from (   select person_id,car_id,row_number() over (partition by person_id order by car_id) as rn   from car_assignment ) t  where rn > 2);