题解 | #查看不同年龄段的用户明细#
计算用户8月每天的练题数量
http://www.nowcoder.com/practice/847373e2fe8d47b4a2c294bdb5bda8b6
select day(date) as day ,count(device_id) as question_cnt from question_practice_detail
where year(date)=2021&&month(date)=8
group by date;
where year(date)=2021&&month(date)=8
group by date;
