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全部文章 / 题解（共80篇）

题解 | 74#考试分数(三)# 来自专栏

select g.id ,name ,score from ( select * ,dense_rank() over(partition by language_id order by score desc) t_rank from grade ) g join la...

2021-08-22

1 410

题解 | 81#牛客的课程订单分析(五)# 来自专栏

select t.user_id ,min(t.date) as first_buy_date ,max(t.date) as second_buy_date ,t.cnt from ( select user_id ,date ,rank() over(partition by user_i...

2021-08-19

0 531

题解 | 82#牛客的课程订单分析(六)# 来自专栏

select o.id ,is_group_buy ,if(is_group_buy='Yes','None',name) client_name from order_info o left join client c on o.client_id=c.id where user_id in ...

2021-08-19

0 331

题解 | 83#牛客的课程订单分析(七)# 来自专栏

select if(is_group_buy='Yes','GroupBuy',name) source,count(*) from order_info o left join client c on o.client_id=c.id where user_id in ( select...

2021-08-18

0 451

题解 | 67#牛客每个人最近的登录日期(二)# 来自专栏

select u.name u_n ,c.name c_n ,date from user u join login l on u.id=l.user_id join client c on c.id=l.client_id where (user_id,date) in ( sele...

2021-08-18

0 329

题解 | 90#获得积分最多的人(二)# 来自专栏

select id ,name ,sum(grade_num) from user u join grade_info g on u.id=g.user_id group by id,name having sum(grade_num) >= all ( select sum(g...

2021-08-17

0 303

题解 | 61#对于employees表中，给出奇数行的first_name# 来自专栏

错误答案： select first_name from (select first_name,rank() over(partition by emp_no order by first_name) rank from employees) t where t.rank%2=1正确答案：因为不能...

2021-08-17

0 339

题解 | 26#汇总各个部门当前员工的title类型的分配数目# 来自专栏

select de.dept_no ,dm.dept_name ,title,count(*) as count from dept_emp de join departments dm on de.dept_no=dm.dept_no join titles t on de.emp_no=t....

2021-08-17

0 332

题解 | 79#牛客的课程订单分析(三)# 来自专栏

select * from order_info where user_id in ( select user_id from order_info a where date>'2025-10-15' and product_name in ('C++',...

2021-08-17

0 363

题解 | 69#牛客每个人最近的登录日期(四)# 来自专栏

select date ,sum(case when (user_id,date) in ( select user_id,min(date) from login group by user_id ) then 1 else 0 end) from login g...

2021-08-17

0 359