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

查询部门最高工资的员工 随笔 第1张

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Department 表包含公司所有部门的信息。

查询部门最高工资的员工 随笔 第2张

编写一个 SQL 查询,找出每个部门工资最高的员工。


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
输出结果:

查询部门最高工资的员工 随笔 第3张

发现最高薪资查出来了,但是名字和薪资对不上
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 )

查询部门最高工资的员工 随笔 第4张

输出结果正确。

第三版:

先查出部门最高工资的思路

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

执行结果

 查询部门最高工资的员工 随笔 第5张

结果正确。

 

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

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

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