DAX rank difference between current and previous months

[maksbotan]

I want to calculate product rank difference between current and previous months

to do so :

1) I calculate current month rank (this work)

Rank_CM = rankx(all('table'[product]),CALCULATE(SUM('table'[qty])))

2) Calculate rank for previous months. It doest work, it returns me same value as (1)

 Rank_LM = CALCULATE([Rank_CM], DATEADD('table'[period].[Date],-1,MONTH))

how can I fix 2?

[olgad]

Hi, when i place your calculations, looks good

You get 1 only there where there is no data in previous month