Thanks man! Unfortunately, I do not think this will work for me because often, the start and end date are the same date. So, the Days between function is always 0 or 1 depending on the hours, so the seconds will always be 86400 or 0. Am I wrong about that? I am pretty new to this date/time calculation stuff.
You could try converting the datetime to a string, then substringing out the various time elements, converting each bit to a numeric and adding them together. Then when you have a number representing the time for each date, subtract them and convert the result back to a date.
Fiddly and probably slow to process. You’d be better off doing it at universe level where you’ve got better functions to manipulate the dates.
The link I posted above provides a way how to do the string manipulations to get the result. As you can see, it’s not very nice. But it’s feasible.
However, as both above posters mentioned, this sort of calculation is better to be done on the database level because a database gives you more functions for the dates manipulations and calculations than what BO can offer.