SELECT
  l.LAB_NAME,
  l.SALARY,
  d.DEP_NAME
FROM
  LABORING l,
  DEPARTAMENT d,
  (SELECT
    MAX(l.SALARY) AS SALARY_MAX
  FROM
    LABORING l,
    DEPARTAMENT d
  WHERE l.DEP_ID = d.DEP_ID
    GROUP BY l.DEP_ID) sq
WHERE l.SALARY = sq.SALARY_MAX
  AND l.DEP_ID = d.DEP_ID