WITH TEMP AS
  (SELECT TO_DATE('01-01-2013 00:00:00','dd-mm-yyyy hh24:mi:ss') DATE1,
    TO_DATE('02-01-2013 00:00:00','dd-mm-yyyy hh24:mi:ss') DATE2
  FROM DUAL
  )
SELECT date2-date1 days,(date2-date1)*24 hours,(date2-date1)*24*60 minutes,(date2-date1)*24*60*60 seconds
FROM temp;

WITH TEMP AS
  (SELECT TO_DATE('01-01-2013 00:00:00','dd-mm-yyyy hh24:mi:ss') DATE1,
    TO_DATE('02-01-2013 06:35:40','dd-mm-yyyy hh24:mi:ss') DATE2
  FROM DUAL
  )
SELECT round(DATE2-DATE1) DAYS,round((DATE2-DATE1)*24) HOURS,round((DATE2-DATE1)*24*60) MINUTES,round((DATE2-DATE1)*24*60*60) SECONDS
FROM temp;