17. 3rd Highest Salary

SELECT * FROM soft_uni.employees;
SELECT
    emp.department_id, MAX(emp.salary) as third_highest_salary
FROM
    employees AS emp
        JOIN
    (SELECT
        e.department_id AS department_id,
            MAX(e.salary) AS max_salary
    FROM
        employees AS e
    JOIN (SELECT
        e.department_id AS department_id,
            MAX(e.salary) AS max_salary
    FROM
        employees AS e
    GROUP BY e.department_id) AS first_max_salary
    ON e.department_id = first_max_salary.department_id
    WHERE
        e.salary < first_max_salary.max_salary
    GROUP BY e.department_id) AS second_max_salary
    ON emp.department_id = second_max_salary.department_id
    WHERE emp.salary < second_max_salary.max_salary
    GROUP BY emp.department_id
    ORDER BY emp.department_id;