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题解 | #牛客每个人最近的登录日期(二)#

select u.name,c.name,l.date from (select *, rank() over(partition by user_id order by date desc) t_rank from login) l inner join user u on l.user_id =...

2024-07-26

1 107

题解 | #牛客每个人最近的登录日期(一)#

select user_id, max(date) id from login group by user_id order by user_id 考察group by注意最近日期用max

2024-07-26

1 153

题解 | #找到每个人的任务#

select p.id, p.name, t.content from person p left join task t on p.id=t.person_id order by p.id 考察连接，要求包括所有人，所以连接要以person表作为连接依据

2024-07-26

1 122

题解 | #刷题通过的题目排名#

select id,number, dense_rank() over(order by number desc) t_rank from passing_number order by t_rank, id 考察窗口函数

2024-07-26

1 116

题解 | #出现三次以上相同积分的情况#

select `number` from grade group by `number` having count(number)>2 考察group by 和having 的用法

2024-07-24

1 161

题解 | #给出employees表中排名#

select a.first_name from ( select emp_no,first_name, row_number() over(order by first_name) row_num_ from employees ) a where a.row_num_%2=1 o...

2024-07-24

2 144

题解 | #running_total 易错题#

select emp_no,salary,sum(salary) over(order by emp_no) from salaries where to_date='9999-01-01' 考察窗口函数的使用利用日期限制当前薪资

2024-07-24

1 150

题解 | #获取有奖金的员工相关信息易错#

select e.emp_no,e.first_name,e.last_name,eb.btype,s.salary, round((case eb.btype when 1 then round(0.1*s.salary,1) when 2 then 0.2*s.salary else 0.3*...

2024-07-24

1 166

题解 | #使用含有关键字exists 易错题#

select * from employees where not exists( select emp_no from dept_emp where employees.emp_no=dept_emp.emp_no ) （ChatGPT）区别与性能考虑执行效率:对于较小的...

2024-07-24

2 172

题解 | #分页查询employees表易错题#

select * from employees limit 5,5 https://blog.nowcoder.net/n/647ec3ec683446b0a3666887caac8489

2024-07-23

1 128