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全部文章（共21篇）

题解 | 统计作答次数

select count(*) total_pv, count(score) complete_pv, (select count(distinct exam_id) from exam_record where score is not null) complete_exa...

2025-05-05

0 27

题解 | SQL类别高难度试卷得分的截断平均值

with sql_score as ( select tag, difficulty, score, row_number() over ( ord...

2025-05-05

0 39

题解 | 查询成绩

select count(*) from ( select count(*) from SC group by sId having ...

2025-03-23

0 32

题解 | 查询下订单用户访问次数？

select t1.user_id,count(*) visit_nums from (select distinct user_id,date_format(order_time,'%Y-%m-%d') order_time from order_tb)t1 join visit_tb t2 on...

2025-03-12

0 39

题解 | 统计每种性别的人数

select 'male',count(profile) from user_submit where profile like '%,male' union select 'female',count(profile) from user_submit where profile like '%f...

2025-03-11

0 43

题解 | 最长连续登录天数

select user_id,max(连续登陆天数) max_consec_days from (select user_id,count(差值) 连续登陆天数 from (select *,day(fdate)-row_number()over(partition by user_id order...

2025-03-09

0 36

题解 | #牛客每个人最近的登录日期(三)#

#先拿出user_id，date这两列去重 #再用窗口函数找出首次登录后下一次登录的日期，计算二者差值是否为1，若为1，就留存成功了 with t1 as ( select distinct user_id, date ...

2024-09-10

0 66

题解 | #牛客每个人最近的登录日期(二)#

select person_name, client_name, date from ( select t2.name person_name, t3.name client_name, ...

2024-09-08

0 71

题解 | #异常的邮件概率#

select distinct date, round(ration, 3) from ( select date, type, send_id, receive...

2024-09-08

0 86

题解 | #给出employees表中排名为奇数行的名#

select first_name from ( select emp_no, first_name, row_number() over ( order by ...

2024-09-08

0 74