Convert time from a format to an int in Oracle - oracle

Question

I can't seem to figure this out. I have some rows with time in the format 00:00:00 (hh:mm:ss) and i need to calculate the total time it takes for a task.
I am unable to sum this data. Can someone advise on a way to convert this to a format i can sum or a method to calculate the total time for the task.
Thanks for any assistance. This is in an Oracle DB.

Answer 1

Convert your time string to a date and subtract the equivalent date at midnight to give you an number as a fraction of a day. You can then sum this number and convert it to an interval:
Oracle Setup:
CREATE TABLE test_data( value ) AS
SELECT '01:23:45' FROM DUAL UNION ALL
SELECT '12:34:56' FROM DUAL UNION ALL
SELECT '23:45:00' FROM DUAL;
Query:
SELECT NUMTODSINTERVAL(
SUM( TO_DATE( value, 'HH24:MI:SS' ) - TO_DATE( '00:00:00', 'HH24:MI:SS' ) ),
'DAY'
) AS total_time_taken
FROM test_data;
Output:
| TOTAL_TIME_TAKEN |
| :---------------------------- |
| +000000001 13:43:41.000000000 |
db<>fiddle here
Update including durations longer than 23:59:59.
Oracle Setup:
CREATE TABLE test_data( value ) AS
SELECT '1:23:45' FROM DUAL UNION ALL
SELECT '12:34:56' FROM DUAL UNION ALL
SELECT '23:45:00' FROM DUAL UNION ALL
SELECT '48:00:00' FROM DUAL;
Query:
SELECT NUMTODSINTERVAL(
SUM(
DATE '1970-01-01'
+ NUMTODSINTERVAL( SUBSTR( value, 1, HM - 1 ), 'HOUR' )
+ NUMTODSINTERVAL( SUBSTR( value, HM + 1, MS - HM - 1 ), 'MINUTE' )
+ NUMTODSINTERVAL( SUBSTR( value, MS + 1 ), 'SECOND' )
- DATE '1970-01-01'
),
'DAY'
) AS total_time
FROM (
SELECT value,
INSTR( value, ':', 1, 1 ) AS HM,
INSTR( value, ':', 1, 2 ) AS MS
FROM test_data
);
Output:
| TOTAL_TIME |
| :---------------------------- |
| +000000003 13:43:41.000000000 |
db<>fiddle here
Even better would be if you changed your table to hold the durations as intervals rather than as strings then everything becomes much simpler:
Oracle Setup:
CREATE TABLE test_data( value ) AS
SELECT INTERVAL '1:23:45' HOUR TO SECOND FROM DUAL UNION ALL
SELECT INTERVAL '12:34:56' HOUR TO SECOND FROM DUAL UNION ALL
SELECT INTERVAL '23:45:00' HOUR TO SECOND FROM DUAL UNION ALL
SELECT INTERVAL '48:00:00' HOUR TO SECOND FROM DUAL;
Query:
SELECT NUMTODSINTERVAL(
SUM( DATE '1970-01-01' + value - DATE '1970-01-01' ),
'DAY'
) AS total_time
FROM test_data;
Output:
| TOTAL_TIME |
| :---------------------------- |
| +000000003 13:43:41.000000000 |
db<>fiddle here