text: /*
  
  The Employee table holds all employees. Every employee has an Id, a salary, and there is also a column for the department Id.
  
  +----+-------+--------+--------------+
  | Id | Name  | Salary | DepartmentId |
  +----+-------+--------+--------------+
  | 1  | Joe   | 70000  | 1            |
  | 2  | Henry | 80000  | 2            |
  | 3  | Sam   | 60000  | 2            |
  | 4  | Max   | 90000  | 1            |
  +----+-------+--------+--------------+
  The Department table holds all departments of the company.
  
  +----+----------+
  | Id | Name     |
  +----+----------+
  | 1  | IT       |
  | 2  | Sales    |
  +----+----------+
  Write a SQL query to find employees who have the highest salary in each of the departments. For the above tables, Max has the highest salary in the IT department and Henry has the highest salary in the Sales department.
  
  +------------+----------+--------+
  | Department | Employee | Salary |
  +------------+----------+--------+
  | IT         | Max      | 90000  |
  | Sales      | Henry    | 80000  |
  +------------+----------+--------+
  
  for more information: https://leetcode.com/problems/department-highest-salary/
  */
  
  #MySQL
  select d.name Department, e1.name Employee, e1.Salary from employee e1
  inner join Department d on e1.DepartmentId = d.Id where e1.Salary in 
  (select max(Salary) from Employee e2 where e1.DepartmentId = e2.DepartmentId);