Working with time difference

I have a measurements like this:

value time
35101 1599719557000000000
35101 1599733107000000000
35102 1599733127000000000

I would to show, maybe in a graph bar, the time difference between the last value and the previous value of a single value. I mean:

difference(1599719557000000000- 1599733107000000000) for value 35101

Is it possible?
I reached this point:

Thank you