How to Find the Difference Between Two Timestamps in Oracle

Problem:

You have two columns of the type timestamp and you want to calculate the difference between them.

Example:

In the travel table, there are three columns: id, departure, and arrival. You'd like to calculate the difference between the arrival and the departure.

The travel table looks like this:

Solution:

SELECT
  id,
  departure,
  arrival,
  arrival - departure AS difference
FROM travel;

The result is:

Discussion:

To calculate the difference between the timestamps in Oracle, simply subtract the start timestamp from the end timestamp (here: arrival - departure). The resulting column will be in INTERVAL DAY TO SECOND. The first number you see is the number of whole days that passed from departure to arrival. Then you'll see the number of full hours, full minutes, and the number of seconds, with any partial second as the decimal place.