Calculate difference between 2 date / times in Oracle SQL

Question

I have a table as follows:

Filename - varchar
Creation Date - Date format dd/mm/yyyy hh24:mi:ss
Oldest cdr date - Date format dd/mm/yyyy hh24:mi:ss

How can I calcuate the difference in hours minutes and seconds (and possibly days) between the two dates in Oracle SQL?

Thanks

Answer 1

You can substract dates in Oracle. This will give you the difference in days. Multiply by 24 to get hours, and so on.

SQL> select oldest - creation from my_table;

If your date is stored as character data, you have to convert it to a date type first.

SQL> select 24 * (to_date('2009-07-07 22:00', 'YYYY-MM-DD hh24:mi') 
             - to_date('2009-07-07 19:30', 'YYYY-MM-DD hh24:mi')) diff_hours 
       from dual;

DIFF_HOURS
----------
       2.5

---

Note:

This answer applies to dates represented by the Oracle data type DATE. Oracle also has a data type TIMESTAMP, which can also represent a date (with time). If you subtract TIMESTAMP values, you get an INTERVAL; to extract numeric values, use the EXTRACT function.