查詢部門最高工資的員工

Employee 表包含所有員工信息，每個員工有其對應的 Id, salary 和 department Id。

Department 表包含公司所有部門的信息。

編寫一個 SQL 查詢，找出每個部門工資最高的員工。

第一版sql：

select Department.name as Department,Employee.Name as Employee,max(Salary) as Salary from Employee 
left join Department on Department.Id = Employee.DepartmentId
group by DepartmentId

輸出結果：

發現最高薪資查出來了，但是名字和薪資對不上
第二版sql:

select d.name as Department,e.name as Employee,Salary
from Employee e
inner join Department d 
on e.DepartmentId=d.id
where e.Salary>=(select max(Salary) as Salary from Employee where DepartmentId = d.id )

輸出結果正確。

第三版：

先查出部門最高工資的思路

select d.name as department,e.name,e.salary from employee e
left JOIN (select id,max(salary) as salary,departmentid from employee GROUP by departmentid)c on e.DepartmentId=c.DepartmentId
left JOIN department d on e.departmentid= d.id
where e.departmentid = c.departmentid and e.salary = c.salary

執行結果

 

結果正確。

 

參考：https://blog.csdn.net/qq_43048011/article/details/82193952

　　   https://blog.csdn.net/qq_20309705/article/details/77865425