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
select tag,difficulty,round((sum(score)-max(score)-min(score))/(count(score)-2),1) from examination_info ei join exam_record er on ei.exam_id=er.exam_id where tag='SQL' and difficulty='hard' round()保留一位小数；平均数总分除以总人数；
