i need to keep a track of the number of hours of travel and time spent onsite for service work.
So far its been a simple matter of creating a start datetime field and an end datetime field with a drop down to pick the correct activity, is there a way however to automatically calculate the difference between the two and present the result in another field?
i can see that you can create a field and then have this calculated but what is the formula for such a field?
originally i thought this formula would be ok "subtract($start_time_c,$end_time_c)" however as the fields are not a number it gives an error message.