#目标司机
with a as
(select distinct driver_id
from tb_get_car_order
where mileage is null
and date_format(order_time,'%Y%m')='202110')

select ifnull(driver_id,'总体'),round(avg(grade),1) as avg_grade

from tb_get_car_order
where driver_id in (select driver_id from a)
and grade is not null
group by driver_id

with rollup 

三刷 with rollup 之前不能加order by