题解 | #每月各旬有多少人练题#
每月各旬有多少人练题
https://www.nowcoder.com/practice/48c8bef6528d4d838e9646682e2b395d
with cte as (
select left(event_date,7) as dt_month,
case when right(event_date,2)<=9 then '上旬'
when right(event_date,2)<=19 then '中旬'
else '下旬' end as dt_days ,count(distinct device_id) as cnt
from question_practice_detail
group by dt_month,dt_days )
select concat(left(dt_month,4),'年',mid(dt_month,6,2),'月',dt_days) as dt_range,cnt
from cte
order by dt_month desc,cnt desc
