I'm trying to create a couple of advanced calcs that just keep failing for me.  I was able to easily get Last Month Sales, and Total Current Year Sales, and Last Year Sales (12 months ago), but I'm not able to get Total of Prior Year Sales by any method I have tried.

Calcs so far:

Sales: SUM(SALES)

Sales LM: WINDOW_SUM(SUM([Sales]), -1, -1)

Sales LY: WINDOW_SUM(SUM([Sales]), -12, -12)

Total Sales This Year:  { INCLUDE [Year of order] : SUM(    { EXCLUDE [Order Date] : SUM([Sales]) }     ) }

Total Sales for Last year:  ???????????