题解 | #SQL类别高难度试卷得分的截断平均值#
SQL类别高难度试卷得分的截断平均值
http://www.nowcoder.com/practice/a690f76a718242fd80757115d305be45
tag,difficulty都在左表,可以使用左连接
select tag, difficulty,
round((sum(score) - max(score) - min(score)) / (count(score) - 2), 1) as clip_avg_score
from exam_record
left join examination_info on examination_info.exam_id = exam_record.exam_id
where tag="SQL" and difficulty="hard"