LeetCode 【困难】数据库-第185：部门工资前三高的所有员工

select 
d.name as Department,
f.name as Employee,
Salary
from department d 
inner join 
(select * from 
(
    select *,
    dense_rank() over (partition by departmentid order by salary desc) as dense_ranks 
    from employee e    # 第一步：先顺序排序
) b
where dense_ranks <= 3   # 第二步：筛选出来前三名，必须在第一步的基础外进行筛选，否则报错
) f 
on d.id = f.departmentid;  # 第三步：连接表、输出结果信息

备注：前三名的筛选，必须是要在排序之后，重新在该表中去筛选。否则报错。