How to get the difference within multiple values in bar chart?

Hi everyone,

Just wanna ask how can I get the difference within the multiple values in tableau?

I have here a bar chart and it shows the data on a monthly basis. 012020, 022020.

Now what I need to do is to get the difference every month to see if there is an increase of decrease.

012020 - 022020

022020 - 032020

03-2020 - 042020

Unfortunately, we connect this directly to our database hence I cant share any dummy file.

Hope someone can help.

Thank you~