I am trying to calculate total Amount in sheet#1 below by referring to sheet#2's [Date Sent to Client] and [Related Opportunity: Amount]:
Sheet#2:
So the Amount in sheet#1
SUMIFS({Sheet#2}[Related Opportunity: Amount], YEAR(Sheet#2[Date Sent to Client]=STC-year), MONTH(Sheet#2[Date Sent to Client]=STC-Month)
I have tried many times but still frustrated to make it work. Thanks