I have followed this Document to get the total messages published in RabbitMQ.
It shows a graph for timeseries that I selected and for each time, it shows a number of messages total published.

But I want to see the relative message published since the time I selected.

For e.g. I chose period from 8 to 12 PM. If the count of messages at 8 AM was 10 and for noon it was 55. I want to see 0 messages at 8 AM and 45 at noon (55 – 10).

What query should be returned to achieve it?