power bi desktop getting difference with calculate

Jinxz_21 , Ideally SUM('sales'[Qnty]) should do

 

I think what you need if

Get_Diff =
VAR __a = CALCULATE(SUM('sales'[Qnty]),'sales'[Year]=2022) // value = 5
VAR __b = CALCULATE(SUM('sales'[Qnty]),'sales'[Year]=2021) // value = 10
VAR __c = CALCULATE(__a - __b) //should be c = -5

return

if(isinscope(Table[Year]), SUM('sales'[Qnty]), _C)

 

or Use TI

 

Time Intelligence, DATESMTD, DATESQTD, DATESYTD, Week On Week, Week Till Date, Custom Period on Period,
Custom Period till date: https://youtu.be/aU2aKbnHuWs&t=145s

Power BI — Year on Year with or Without Time Intelligence
https://medium.com/@amitchandak.1978/power-bi-ytd-questions-time-intelligence-1-5-e3174b39f38a
https://www.youtube.com/watch?v=km41KfM_0uA