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全部文章（共74篇）

题解 | 第二快/慢用时之差大于试卷时长一半的试卷

with t as (select ei.exam_id as exam_id,duration, timestampdiff(second,start_time,submit_time)/60 as time_record, rank()over(partition by exam_id orde...

2025-09-25

0 19

题解 | 第二快/慢用时之差大于试卷时长一半的试卷

with t as (select ei.exam_id as exam_id,duration, timestampdiff(second,start_time,submit_time)/60 as time_record, rank()over(partition by exam_id orde...

2025-09-25

0 15

题解 | 每类试卷得分前3名

select tag,uid,ranking from ( select tag,uid, rank()over(partition by tag order by max(score) desc,min(score) desc,uid desc) as ranking from examinati...

2025-09-25

0 13

题解 | 每个6/7级用户活跃情况

with t1 as (select uid, count(distinct date_format(submit_time,'%Y-%m')) as act_month_total from (select uid,submit_time from exam_record union all ...

2025-09-24

0 22

题解 | 满足条件的用户的试卷完成数和题目练习数

with er_2 as (select ui.uid as uid, level, tag, difficulty, er.submit_time as submit_time,er.score as score from user_info ui join exam_record er on ...

2025-09-24

0 14

题解 | 分别满足两个活动的人

with t1 as (select difficulty,uid,score,duration,timestampdiff(second,start_time,submit_time)/60 as finish_time from examination_info ei join exam_rec...

2025-09-23

0 17

题解 | 分别满足两个活动的人

with t1 as (select difficulty,uid,score,duration,timestampdiff(second,start_time,submit_time)/60 as finish_time from examination_info ei join exam_rec...

2025-09-23

0 14

题解 | 每个题目和每份试卷被作答的人数和次数

select exam_id as tid,count(distinct uid) as uv,count(exam_id) as pv from exam_record group by exam_id union all select question_id as tid,count(dis...

2025-09-23

0 15

题解 | 每个题目和每份试卷被作答的人数和次数

with t1 as (select exam_id as tid,count(distinct uid) as uv,count(exam_id) as pv from exam_record group by exam_id order by uv desc,pv desc), t2 as (...

2025-09-23

0 20

题解 | 试卷发布当天作答人数和平均分

with merged_table as (select ui.uid,level,tag,score,release_time, start_time,submit_time,ei.exam_id as exam_id from user_info ui join exam_record er ...

2025-09-19

0 17