题解 | #对试卷得分做min-max归一化#
对试卷得分做min-max归一化
https://www.nowcoder.com/practice/2b7acdc7d1b9435bac377c1dcb3085d6
select uid,exam_id, round(if(max_score-min_score>0,(avg(score-min_score)/(max_score-min_score)*100),sum(score)),0) as avg_new_score from (select exam_id, min(score) as min_score, max(score) as max_score from exam_record join examination_info using(exam_id) where difficulty='hard' and score is not null group by exam_id) as score_list join exam_record using(exam_id) where score is not null group by uid,exam_id order by exam_id,avg_new_score desc