题解 | #统计复旦用户8月练题情况#

select a.device_id,
        a.university,
        count(question_id) as question_cnt,
        sum(
          if(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 and month(b.date)='08'
where a.university = "复旦大学" 
group by a.device_id