Create a report that contains 3 objects: Country, Year, Revenue
Add table with expression
=Sum(If([Year] Between ("FY2004";"FY2006"); [Revenue]; 0))
Add section by Country
Everything looks nice
Now add new query with only Year.
Now the expression produces null result. But why???
To see the numbers again, you can either unmerge Year (which is usually not an option)
or enable Extend merged dimension values
It is still not clear why this helps.