题解 | #有取消订单记录的司机平均评分#
有取消订单记录的司机平均评分
https://www.nowcoder.com/practice/f022c9ec81044d4bb7e0711ab794531a
select ifnull(driver_id,"总体")as driver_id,round(avg(grade),1)'平均评分' from tb_get_car_order where driver_id in (select driver_id from tb_get_car_order where date_format(order_time,'%Y-%m')='2021-10'and isnull(fare))and not isnull(grade) group by driver_id with rollup;
有点不理解ifnull(driver_id,"总体")as driver_id 和最后面的with rollup的用法！！！！！！！！！！
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