First Attempt for solution

solution.sql

/*
employees                             projects
+---------------+---------+           +---------------+---------+
| id            | int     |<----+  +->| id            | int     |
| first_name    | varchar |     |  |  | title         | varchar |
| last_name     | varchar |     |  |  | start_date    | date    |
| salary        | int     |     |  |  | end_date      | date    |
| department_id | int     |--+  |  |  | budget        | int     |
+---------------+---------+  |  |  |  +---------------+---------+
                             |  |  |
departments                  |  |  |  employees_projects
+---------------+---------+  |  |  |  +---------------+---------+
| id            | int     |<-+  |  +--| project_id    | int     |
| name          | varchar |     +-----| employee_id   | int     |
+---------------+---------+           +---------------+---------+
*/

SELECT e.first_name, e.last_name, e.salary,
  d.name as department_name
FROM employees   AS e
JOIN departments AS d ON e.department_id = d.id

 first_name | last_name | salary | department_name 
------------+-----------+--------+-----------------
 Pancho     | Villa     |  15000 | Reporting
 John       | Smith     |  20000 | Reporting
 Ian        | Peterson  |  80000 | Engineering
 Mike       | Peterson  |  20000 | Engineering
 Cailin     | Ninson    |  30000 | Engineering
 John       | Mills     |  50000 | Marketing
 Ava        | Muffinson |  10000 | Silly Walks
(7 rows)

/* seleccionar top two salario por departamento */
SELECT d.name as dept, e.first_name, e.salary
FROM (
   SELECT id, first_name, department_id, salary,
          rank() over (partition by department_id order by salary desc) as rank 
   FROM EMPLOYEES order by salary desc, rank asc
) e, DEPARTMENTS d
WHERE rank <= 2 and e.department_id = d.id

    dept     | first_name | salary 
-------------+------------+--------
 Reporting   | Pancho     |  15000
 Reporting   | John       |  20000
 Engineering | Cailin     |  30000
 Engineering | Ian        |  80000
 Marketing   | John       |  50000
 Silly Walks | Ava        |  10000
(6 rows)