SQL 185. 部门工资前三高的员工

题目：

Employee 表包含所有员工信息，每个员工有其对应的 Id, salary 和 department Id 。

±—±------±-------±-------------+
| Id | Name | Salary | DepartmentId |
±—±------±-------±-------------+
| 1 | Joe | 70000 | 1 |
| 2 | Henry | 80000 | 2 |
| 3 | Sam | 60000 | 2 |
| 4 | Max | 90000 | 1 |
| 5 | Janet | 69000 | 1 |
| 6 | Randy | 85000 | 1 |
±—±------±-------±-------------+
Department 表包含公司所有部门的信息。

±—±---------+
| Id | Name |
±—±---------+
| 1 | IT |
| 2 | Sales |
±—±---------+
编写一个 SQL 查询，找出每个部门工资前三高的员工。例如，根据上述给定的表格，查询结果应返回：

±-----------±---------±-------+
| Department | Employee | Salary |
±-----------±---------±-------+
| IT | Max | 90000 |
| IT | Randy | 85000 |
| IT | Joe | 70000 |
| Sales | Henry | 80000 |
| Sales | Sam | 60000 |
±-----------±---------±-------+

Create table If Not Exists Employee (Idint, Name varchar(255), Salary int, DepartmentId int);
Create table If Not Exists Department (Idint, Name varchar(255));
Truncate table Employee;
insert into Employee (Id, Name, Salary,DepartmentId) values ('1', 'Joe', '70000', '1');
insert into Employee (Id, Name, Salary,DepartmentId) values ('2', 'Henry', '80000', '2');
insert into Employee (Id, Name, Salary,DepartmentId) values ('3', 'Sam', '60000', '2');
insert into Employee (Id, Name, Salary,DepartmentId) values ('4', 'Max', '90000', '1');
insert into Employee (Id, Name, Salary,DepartmentId) values ('5', 'Janet', '69000', '1');
insert into Employee (Id, Name, Salary,DepartmentId) values ('6', 'Randy', '85000', '1');
Truncate table Department;
insert into Department (Id, Name) values('1', 'IT');
insert into Department (Id, Name) values('2', 'Sales');

答案1

select d.Name Department ,e1.Name Employee,e1.Salary Salary 
from Employee e1
inner join Department d on e1.DepartmentId= d.Id
where 3 >= (
           select count(distinct(e2.Salary)) from Employee e2 where e2.Salary >=e1.Salary and e2.DepartmentId=d.Id
       ) order by d.Name,e1.Salary Desc;