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MySQL试题答案解析

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题解 | #考试分数(三)# 来自专栏

/* select language_id, score, DENSE_RANK() over (order by score) as s from grade group by language_id; */ select score_rank.id, name, score_rank.score...

Mysql

2021-10-13

0 437

题解 | #牛客每个人最近的登录日期(四)# 来自专栏

-- 第一步：新用户临时表 select user_id, min(date) as m_date from login group by user_id; -- 第二步：根据日期，统计人数，得出有新用户登录时的日期及其数量 select m_date, count(distinct use...

Mysql

2021-10-10

0 418

题解 | #牛客每个人最近的登录日期(三)# 来自专栏

select round(c_user_id/t_user_id,3) as q from (select count(distinct user_id) as t_user_id from login) as t, (select count(mmt.user_id) as c_user_id...

Mysql

2021-10-10

0 391

题解 | #网易云音乐推荐(网易校招笔试真题)# 来自专栏

/* select follower_id from follow where user_id = 1; select music_id from music_likes as ml where user_id = 1; select music_id from music_likes as m...

Mysql

2021-10-10

0 515

题解 | #考试分数(一)# 来自专栏

select job, ROUND(avg(score),3) as avg from grade group by job order by avg(score) desc; split好像没有用到呢

Mysql

2021-10-09

0 335

题解 | #牛客每个人最近的登录日期(二)# 来自专栏

/* select user_id, max(data) as d from login group by user_id; */ select u.name as u_n, c.name as c_n, ud.d as u_date from client as c, user as u, lo...

Mysql

2021-10-08

0 463

题解 | #异常的邮件概率# 来自专栏

select date, ROUND(AVG(CASE WHEN type = 'no_completed' THEN 1 ELSE 0 END),3) AS p from email where send_id not in (select id from user where is_b...

Mysql

2021-10-08

0 342

题解 | #对于employees表中，给出奇数行的first_name# 来自专栏

/* select first_name, (DENSE_RANK() over (order by first_name)) as f_rank from employees */ select first_name from ( select *, (DENSE_RANK() over ...

Mysql

2021-10-08

0 500

题解 | #找到每个人的任务# 来自专栏

select p.id, name, content from person as p left outer join task as t on p.id = t.person_id order by p.id; hahaha，这道题对我提了一个醒，要注意表中的数据格式与内容，不要想当然的认为两...

Mysql

2021-10-07

0 311

题解 | #牛客的课程订单分析(二)# 来自专栏

方法1 select user_id from( select user_id,count(user_id) as cud from ( select * from order_info where date > '2025-10...

Mysql

2021-10-07

0 397