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题解 | 未完成试卷数大于1的有效用户

select uid, count(*)-count(submit_time) as incomplete_cnt, count(submit_time) as complete_cnt, group_concat(distinct concat_ws(':',date(start_time),ta...

2025-05-02

0 33

题解 | 满足条件的用户的试卷完成数和题目练习数

#7级大佬 with t as ( select u.uid,avg(er.score) as avg_score from user_info u left join exam_record er on u.uid=er.uid left join pra...

2025-05-01

0 32

题解 | 某乎问答最大连续回答问题天数大于等于3天的用户及其对应等级

select at.author_id, author_level, max(cnt) as days_cnt from( select author_id,count(primary_date) as cnt from( select author_id, date_sub(answer_da...

2025-04-30

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题解 | 某乎问答回答过教育类问题的用户里有多少用户回答过职场类问题

select count(*) as num from answer_tb a join issue_tb i on a.issue_id = i.issue_id where a.author_id in ( select distinct a.author_id from answer_t...

2025-04-30

0 26

题解 | 某乎问答单日回答问题数大于等于3个的所有用户

select date(answer_date),author_id, count(*) as answer_cut from answer_tb where substr(answer_date,1,7)='2021-11' group by date(answer_date),author_id...

2025-04-30

0 35

题解 | 某乎问答高质量的回答中用户属于各级别的数量

select (case when author_level between 1 and 2 then '1-2级' when author_level between 3 and 4 then '3-4级' else '5-6级' end ) as level_cut, count(an...

2025-04-29

0 22

题解 | 某乎问答11月份日人均回答量

select date(answer_date), round(count(*)/count(distinct author_id),2) as per_num from answer_tb where substr(answer_date,1,7)='2021-11' group by date(...

2025-04-29

0 20

题解 | 牛客直播各科目同时在线人数

with t as( select in_datetime dt,course_id, 1 as type from attend_tb union all select out_datetime dt,course_id, -1 as type from attend_...

2025-04-28

0 29

题解 | 牛客直播各科目出勤率

select c.course_id,course_name, round(count(distinct case when timestampdiff(minute,in_datetime,out_datetime)>=10 then a.user_id else null end )*10...

2025-04-28

0 26

题解 | 牛客直播各科目平均观看时长

select course_name, round(avg(timestampdiff(second,in_datetime,out_datetime)/60),2) as avg_Len from course_tb c join attend_tb a on c.course_id = a....

2025-04-28

0 23