题解 | #21年8月份练题总数#
21年8月份练题总数
https://www.nowcoder.com/practice/b8f30b239b454ed490367b53ea95607d
select count(distinct device_id) as did_cnt,count(question_id) as question_cnt from question_practice_detail where month(date) = 8
where date like "2021-08%" 最标准的写法
所有练习过题目的总用户数 distinct关键字