Oracle - Best SELECT statement for getting the dif

Question

I'm attempting to fulfill a rather difficult reporting request from a client, and I need to find away to get the difference between two DateTime columns in minutes. I've attempted to use trunc and round with various formats and can't seem to come up with a combination that makes sense. Is there an elegant way to do this? If not, is there any way to do this?

Answer 1

By default, oracle date subtraction returns a result in # of days.

So just multiply by 24 to get # of hours, and again by 60 for # of minutes.

Example:

select
  round((second_date - first_date) * (60 * 24),2) as time_in_minutes
from
  (
  select
    to_date('01/01/2008 01:30:00 PM','mm/dd/yyyy hh:mi:ss am') as first_date
   ,to_date('01/06/2008 01:35:00 PM','mm/dd/yyyy HH:MI:SS AM') as second_date
  from
    dual
  ) test_data

Answer 2

http://asktom.oracle.com/tkyte/Misc/DateDiff.html - link dead as of 2012-01-30

Looks like this is the resource:

http://asktom.oracle.com/pls/asktom/ASKTOM.download_file?p_file=6551242712657900129

Answer 3

SELECT date1 - date2
  FROM some_table

returns a difference in days. Multiply by 24 to get a difference in hours and 24*60 to get minutes. So

SELECT (date1 - date2) * 24 * 60 difference_in_minutes
  FROM some_table

should be what you're looking for