Possibility to use deltas between samples

[lefred]

It would be great if there will be the possibility to explicitly use deltas for samples.

For example I've a sample that returns the amount of queries run a database since the start of it. This counter just keep increasing but I would like to only display the value between two collected samples.

If the value is 3021, then 3222, then 3232, I would like to have the possibility to display: 0, 201, 10

If this is already possible, I didn't find it yet ;)

Cheers,