题解 | #统计复旦用户8月练题情况#
统计复旦用户8月练题情况
https://www.nowcoder.com/practice/53235096538a456b9220fce120c062b3
select a.device_id,a.university,count(question_id) question_cnt,sum(if(b.result='right',1,0)) as right_question_cnt
from
user_profile a left join
question_practice_detail b
on
a.device_id=b.device_id
where a.university='复旦大学' and (month(b.date)=8 or month(b.date) is null)
group by a.device_id;
