How to add calculate last year ccolumn per month?

Hi

My query contains three fields:

Year , Month and amount.

I try to add another column to display the amount calculated last year per month

I tried this formula, but it returns empty:

first I created a new variable calles "last year" = [year]-1

and then I tried to do : [amount] where([year] = [last year] but it returns empty

Example (in red the column that I want to add)

Is it possible?