selectDATE_FORMAT(date,'%e') as day,count(question_id)from question_practice_detailWHEREDATE_FORMAT(date,'%Y-%m')='2021-08'group by day DATE_FORMAT(date,'%Y-%m')='2021-08'筛选出八月份DATE_FORMAT(date,'%e') as day 在求出天,进行分组,聚合函数求出8月份每天练题次数