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
https://www.nowcoder.com/practice/5b58e89556dc4153a79d8cf8c08ba499
select
er.exam_id,
count(distinct er.uid) as uv,
round(avg(score),1) as avg_score
from
exam_record er
inner join
examination_info ei on er.exam_id = ei.exam_id
inner join
user_info ui on er.uid = ui.uid
where
ui.level > 5 and ei.tag = 'SQL'
and date_format(ei.release_time,'%Y%m') = date_format(er.start_time,'%Y%m')
group by
1
order by
2 desc,3
