题解 | #浙大不同难度题目的正确率#
SQL类别高难度试卷得分的截断平均值
http://www.nowcoder.com/practice/a690f76a718242fd80757115d305be45
SELECT rt.tag,rt.difficulty, ROUND((sum(score) -max(score) -min(score))/ (count(score)-2),1) as clip_avg_score from exam_record er join examination_info rt USING(exam_id) where rt.tag='SQL' and rt.difficulty='hard';