Oracle - Calculo de tiempo entre dos fechas

CREATE PROCEDURE SPBICALCULARTIEMPOSERVICIO

AS

BEGIN

  DECLARE

  @LRMTHVEX INTEGER,

  @LCODEMPL NUMERIC(13),

  @LFECINGR DATETIME,

  @LFECHA datetime,

  @LTMPFECH datetime,

  @LANIOS int,

  @LMESES int,

  @LDIAS int

  DECLARE C_HVEXT CURSOR FOR (SELECT RMT_HVEX, COD_EMPL, FEC_INGR FROM BI_HVEXT WHERE EMP_ACTU = 'S');

  OPEN C_HVEXT;

  FETCH NEXT FROM C_HVEXT INTO @LRMTHVEX, @LCODEMPL, @LFECINGR;

  WHILE @@FETCH_STATUS = 0

  BEGIN

	SELECT @LFECHA = @LFECINGR

	SELECT @LTMPFECH = @LFECHA

	SELECT @LANIOS = DATEDIFF(yy, @LTMPFECH, GETDATE()) - CASE WHEN (MONTH(@LFECHA) > MONTH(GETDATE())) OR (MONTH(@LFECHA) = MONTH(GETDATE()) AND DAY(@LFECHA) > DAY(GETDATE())) THEN 1 ELSE 0 END

	SELECT @LTMPFECH = DATEADD(yy, @LANIOS, @LTMPFECH)

	SELECT @LMESES = DATEDIFF(m, @LTMPFECH, GETDATE()) - CASE WHEN DAY(@LFECHA) > DAY(GETDATE()) THEN 1 ELSE 0 END

	SELECT @LTMPFECH = DATEADD(m, @LMESES, @LTMPFECH)

	SELECT @LDIAS = DATEDIFF(d, @LTMPFECH, GETDATE())

	SELECT @LRMTHVEX, @LANIOS, @LMESES, @LDIAS

	UPDATE BI_HVEXT SET ANO_SERV = @LANIOS,MES_SERV = @LMESES, DIA_SERV = @LDIAS;

    FETCH NEXT FROM C_HVEXT INTO @LRMTHVEX, @LCODEMPL, @LFECINGR;

  END;

  CLOSE C_HVEXT;

  DEALLOCATE C_HVEXT;

END;

GO

SELECT TRUNC(MONTHS_BETWEEN(TO_DATE('23/02/2016', 'DD/MM/YYYY'),

                            TO_DATE('23/05/1992', 'DD/MM/YYYY')) / 12) AS ANIOS

     , TRUNC(MOD(MONTHS_BETWEEN(TO_DATE('23/02/2016', 'DD/MM/YYYY'),

                                TO_DATE('23/05/1992', 'DD/MM/YYYY')), 12)) AS MESES

     , TRUNC(TO_DATE('23/02/2016', 'DD/MM/YYYY') -

             ADD_MONTHS(TO_DATE('23/05/1992', 'DD/MM/YYYY'), TRUNC(MONTHS_BETWEEN(TO_DATE('23/02/2016', 'DD/MM/YYYY'),

                                                                                  TO_DATE('23/05/1992', 'DD/MM/YYYY'))))) AS DIAS

FROM   DUAL

;