题解 | #0级用户高难度试卷的平均用时和平均得分#
0级用户高难度试卷的平均用时和平均得分
https://www.nowcoder.com/practice/bb474c6cbd77478fb6d9fc86934d0ebb
select distinct ui.uid, round(sum(score)/count(*),0) as avg_score, round(avg(if(submit_time is null,duration,timestampdiff(minute,start_time,submit_time))),1) as avg_time_took from (user_info ui left join exam_record er on ui.uid=er.uid) left join examination_info ei on ei.exam_id=er.exam_id where level =0 and difficulty = 'hard' group by uid
