Need difference in date in hh24:mi:ss format

Question

Have 2 date fields in a table. Need the difference between the dates in hh:mi:ss format
Here is my table:
create table test(
ID number,
StartDate date,
FinishDate date,
DateDifference varchar2(13));
Here is my record:
insert into test values (1, to_date('01/21/2010 10:05:10','mm/dd/yyyy hh:mi:ss'), to_date('01/21/2010 11:05:10','mm/dd/yyyy hh:mi:ss'), NULL);
Want to populate the DateDifference field as difference between FinishDate and StartDate which in this case would be: 01:00:00. Format needs to be hh:mi:ss.

Answer 1

Hi,
As long as the differences are less than 24 hours, you can say somehting like:
UPDATE     test
SET     DateDifference = TO_CHAR ( TRUNC (SYSDATE) + ( FinishDate
                                               - StartDate
                     , 'HH24:MI:SS'
;For longer amounts of time, you can extract part of an INTERVAL DAY TO SECOND:
UPDATE     test
SET     DateDifference = SUBSTR ( NUMTODSINTERVAL ( FinishDate - StartDate
                                          , 'DAY'
                    , 7
                    , 13
Thanks for posting the sample data in such a nice form!
Even in a simple job it helps.
Edited by: Frank Kulash on Jan 22, 2010 2:15 PM
Had better idea for difference >= 24 hours.