display the department ID, full name (first and last name), salary for those employees who is highest salary in every department.
SELECT first_name ,   last_name ,   salary ,  department_id ,  MAX(salary) FROM employees GROUP BY department_id
Her departmanda en yüksek maaş olan çalışanlar için departman kimliğini, tam adı (ad ve soyadı), maaş görüntüleyin.