题解 | #试卷发布当天作答人数和平均分#
试卷发布当天作答人数和平均分
http://www.nowcoder.com/practice/5b58e89556dc4153a79d8cf8c08ba499
select er.exam_id as exam_id,
count(distinct er.uid) as uv,
round(avg(score),1) as avg_score
from exam_record as er
left join examination_info using(exam_id)
left join user_info using(uid)
where level>5 and tag='SQL' and date(start_time)=date(release_time)
group by exam_id
order by uv desc,avg_score asc
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