select floor(months_between(date '2012-10-10', date '2011-10-10') /12) from dual;
select floor(months_between(date '2012-10-9' , date '2011-10-10') /12) from dual;
SELECT (END_DT - START_DT) * 60 * 60 * 24 FROM MY_TABLE; -- Seconds
SELECT (END_DT - START_DT) * 60 * 24 FROM MY_TABLE; -- Minutes
SELECT (END_DT - START_DT) * 24 FROM MY_TABLE; -- Hours