Função Oracle LAST DAY

-- RETORNA O ULTIMO DIA DO MÊS

SELECT TRUNC(SYSDATE) AS Data_atual,
       LAST_DAY(TRUNC(SYSDATE)) AS ultimo_dia_mes
  FROM dual;

SELECT LAST_DAY(TO_DATE('10/02/2016', 'DD/MM/YY')) AS ultimo_dia_mes
  FROM dual;

SELECT hire_date, LAST_DAY(hire_date) AS Ultimo_dia_mes
  FROM hr.employees
 WHERE employee_id =114;