Difference between two dates in hourss/minutes in Oracle.

We might need to find the difference between two dates columns in hours/minutes in many cases. Like trying to find how long some program ran. One of the easiest way I found is

SELECT to_number( to_char(to_date('1','J') +
(date1 - date2), 'J') - 1) days,
to_char(to_date('00:00:00','HH24:MI:SS') +
(date1 - date2), 'HH24:MI:SS') time
FROM mytable;