How does one get the time difference between two date columns?

Oracle allows two date values to be subtracted from each other returning a numeric value indicating the number of days between the two dates (may be a fraction). This example will show how to relate it back to a time value.

Let’s investigate some solutions. Test data:

CREATE TABLE dates (date1 DATE, date2 DATE);
INSERT INTO dates VALUES (SYSDATE, SYSDATE-1);
INSERT INTO dates VALUES (SYSDATE, SYSDATE-1/24);
INSERT INTO dates VALUES (SYSDATE, SYSDATE-1/60/24);
SELECT (date1 - date2) FROM dates;

DATE1-DATE2
-----------
1
.041666667
.000694444

Solution 1

SELECT floor(((date1-date2)*24*60*60)/3600)
|| ' HOURS ' ||
floor((((date1-date2)*24*60*60) -
floor(((date1-date2)*24*60*60)/3600)*3600)/60)
|| ' MINUTES ' ||
round((((date1-date2)*24*60*60) -
floor(((date1-date2)*24*60*60)/3600)*3600 -
(floor((((date1-date2)*24*60*60) -
floor(((date1-date2)*24*60*60)/3600)*3600)/60)*60) ))
|| ' SECS ' time_difference
FROM dates;

TIME_DIFFERENCE
--------------------------------------------------------------------------------
24 HOURS 0 MINUTES 0 SECS
1 HOURS 0 MINUTES 0 SECS
0 HOURS 1 MINUTES 0 SECS

An enhancement to solution 1

SELECT floor((date1-date2)*24)
|| ' HOURS ' ||
mod(floor((date1-date2)*24*60),60)
|| ' MINUTES ' ||
mod(floor((date1-date2)*24*60*60),60)
|| ' SECS ' time_difference
FROM dates;</code>

TIME_DIFFERENCE
--------------------------------------------------------------------------------
24 HOURS 0 MINUTES 0 SECS
1 HOURS 0 MINUTES 0 SECS
0 HOURS 1 MINUTES 0 SECS

Solution 2

If you don’t want to go through the floor and ceiling math, try this method (contributed by Erik Wile):

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 dates;

DAYS TIME
---------- --------
1 00:00:00
0 01:00:00
0 00:01:00

Solution 3: If u want an easier method, use numtodsinterval()

Submitted by Shilpa Petrim

NUMTODSINTERVAL: This function is new to Oracle 9i. It takes two arguments numtodsinterval(x,c) where x is a number and c is a character string denoting the units of x. Valid units are ‘DAY’, ‘HOUR’, ‘MINUTE’ and ‘SECOND’.

This function converts the number x into an INTERVAL DAY TO SECOND datatype.

select numtodsinterval(date1-date2,'day') time_difference from dates;
TIME_DIFFERENCE
----------------------------------------------------------------
+000000001 00:00:00.000000000
+000000000 01:00:00.000000000
+000000000 00:01:00.000000000

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