部门工资最高的员工

题目

解析

第一步：在emploee表中找到最大的工资以及部门ID，这样做的好处是可以避免有多个人工资都最高
第二步：内连接后，查找题上给定的字段，条件是工资与ID在第一步查找的表中

• 第一步

SELECT
    DepartmentId, MAX(Salary)
FROM
    Employee
GROUP BY DepartmentId;

结果：

• 第二步

select d.Name as Department,e.Name as Employee, e.Salary 
from Employee as e inner join Department as d 
on e.DepartmentId = d.Id 
where (e.DepartmentId, e.Salary) in 
(select DepartmentId, max(Salary) from Employee group by DepartmentId)