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 device_id,university,
count(question_id) as question_cnt,
sum(if(result='right',1,0)) as right_question_cnt
FROM (select a.device_id,university,question_id,result,date
from user_profile a
left JOIN question_practice_detail b
on a.device_id = b.device_id and month(date)=8
where university = '复旦大学') a
group by device_id
count(question_id) as question_cnt,
sum(if(result='right',1,0)) as right_question_cnt
FROM (select a.device_id,university,question_id,result,date
from user_profile a
left JOIN question_practice_detail b
on a.device_id = b.device_id and month(date)=8
where university = '复旦大学') a
group by device_id
