前述

推荐阅读：通俗易懂的学会：SQL窗口函数

题目描述

leetcode题目 185. 部门工资前三高的所有员工

思路

• 先按照departmentId分组，再按照salary排序 ==>窗口函数dense_rank() over()

select B.name as Department,A.name as Employee,A.salary as Salary
from (select *,dense_rank() over(partition by departmentId order by salary desc) as rk from Employee
) A 
join Department B 
on B.id = A.departmentId
where A.rk <= 3

注意：区分窗口函数rank()、dense_rank()、row_number()

1. rank()

2. dense_rank()

3. row_number()