SELECT
  l.LAB_NAME,
  l.SALARY,
  d.DEP_NAME
FROM
  LABORING l,
  DEPARTAMENT d,

(SELECT
  d.DEP_ID,
  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.DEP_ID = sq.DEP_ID
    AND l.SALARY = sq.SALARY_MAX
    AND d.DEP_ID = sq.DEP_ID