sselect ifnull(driver_id,'总体') driver_id,
       round(avg(grade),1) avg_grade
from tb_get_car_order a
left join tb_get_car_record b
on a.order_id = b.order_id
where (start_time is not null) 
   
      and driver_id in (select driver_id
                        from tb_get_car_order b
                        where (start_time is null)
                        and (DATE_FORMAT(finish_time,'%Y-%m') = '2021-10'))
group by driver_id with ROLLUP