reset global field?

[CarlosB]

Hello, I have i doubt, probably a very simple one but i couldn't find any post that helped me. I have a global field called sum_min which is supposed to sum the value (minutes) of a field of all records. I'm using this calculation to do this:

sum_min = sum_min + minutes.

The problem is that whenever i change the value in the minute field, it adds the sum of all the minutes field on the value in the sum_min, so if i have 20 min in the sum_min, and i add 1 minute in the minutes field,the sum_min will now be 41 and not 21. I could fix this by setting sum_min to 0 before the calculation, but i don't know how =/ Can anybody help me? I'd really appreciate it1 Thanks!

[David Jondreau]

Using a global with that calculation is not the way to sum fields. A Summary field is used for this purpose.

[CarlosB]

thanks a lot for you answer, ik changed it now and it work perfectly :(