题解 | #每个题目和每份试卷被作答的人数和次数#
每个题目和每份试卷被作答的人数和次数
http://www.nowcoder.com/practice/203d0aed8928429a8978185d9a03babc
select * from (
select exam_id as tid,count(distinct uid) as uv,
count(start_time) as pv from
exam_record group by exam_id order by uv desc ,pv desc) t1
UNION
select * from (
select question_id,count(distinct uid) as uv ,
count(submit_time) as pv
from practice_record group by question_id
order by uv desc,pv desc) t2
