题解 | #21年8月份练题总数#
21年8月份练题总数
http://www.nowcoder.com/practice/b8f30b239b454ed490367b53ea95607d
select
count(distinct device_id) as did_cnt,
count(question_id)as question_cnt
from
question_practice_detail
where
year(date)= 2021
and month(date) = 8
// where 的内容要用 and 连接