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题解 | #考试分数(三)#

select t.id id,name,score from(select g.id,name,score,dense_rank()over(partition by name order by score desc) dk from grade g left join language l on ...

2023-12-06

0 183

题解 | #考试分数(二)#

select id,g.job job,g.score score from grade g left join (select job,avg(score) ascore from grade group by job) t on g.job=t.job where g.score>t.as...

2023-12-05

0 212

题解 | #考试分数(一)#

select job,round(avg(score),3) from grade group by job order by avg(score) desc

2023-12-05

0 168

题解 | 问GPT之前先动手画个表格把关系梳理清楚

select name u_n,lo.date date,sum(number)over(partition by lo.user_id order by lo.date) ps_num from login lo right join passing_number pn on lo.user_id...

SQL错题

2023-12-05

1 247

题解 | #牛客每个人最近的登录日期(四)#

# 每个日期新登录个数 /*SELECT dates.date, IFNULL(new_users.new, 0) AS new FROM ( SELECT DISTINCT date FROM login ) AS dates LEFT JOIN ( SELECT f...

SQL错题

2023-12-03

0 229

题解 | where exists

SELECT ROUND( (SELECT COUNT(DISTINCT user_id) FROM login a WHERE EXISTS ( SELECT 1 FROM login AS b WHERE a...

SQL错题

2023-12-03

0 314

题解 | #异常的邮件概率#

SELECT date, ROUND((nc / cnt), 3) FROM ( SELECT date, COUNT(CASE WHEN type = 'no_completed' THEN 1 END) nc...

2023-11-26

0 230

题解 | 很多问题冷静下来多思考也就迎刃而解了

select u_n,c_n,date from(select u.name u_n,c.name c_n,date,row_number()over(partition by u.name order by date desc) rn from login l join user u on l.u...

2023-11-26

0 250

题解 | #牛客每个人最近的登录日期(一)#

select user_id,id from(select user_id,date id,row_number()over(partition by user_id order by date desc) rn from login) t where rn=1 order by user_id

2023-11-26

1 307

题解 | #找到每个人的任务#

select p.id,name,content from person p left join task t on p.id=t.person_id

2023-11-25

0 199