select sysdate + 1/24 from dual;
sysdate is a function without arguments which returns DATE type
+ 1/24 adds 1 hour to a date
select to_char(to_date('2014-10-15 03:30:00 pm', 'YYYY-MM-DD HH:MI:SS pm') + 1/24, 'YYYY-MM-DD HH:MI:SS pm') from dual;