Optimizing an old SQLBI Article (AND logic in slicers) – Unplugged #4 (18:10)

https://www.sqlbi.com/tv/optimizing-an-old-sqlbi-article-and-logic-in-slicers-unplugged-4/ 

Rewrite old code:

VAR NumOfSelectedCategories = COUNTROWS(VALUES('Product'[Category]))

VAR CustomersAndCategories = SUMMARIZE(Sales, Sales[CustomerKey], Product[Category])

VAR CustomersWithNumCategories = GROUPBY(CustomerAndCategories, "@Categories",  SUMX(CURRENTGROUP(), 1))

VAR Result = COUNTROWS(FILTER(CustomersWithNumCategories, [@NumCategories] = NumOfSelectedCategories))

RETURN Result