LeetCode 184. Department Highest Salary（找出每个部门中最高薪水）

第一种情况：普通情况

第二种情况：

 

第三种情况：

 

 

结果：

select

t1.Name as Employee,t1.Salary as Salary,t2.Name as Department

from

Employee t1 left join Department t2 on t1.DepartmentId=t2.Id

where (t1.DepartmentId,t1.Salary) in (select t4.DepartmentId, max(t4.salary) as s from Employee t4 group by t4.DepartmentId) and t2.Id is not null