Adding Calculations to the Cube - Expert Cube Development with SSAS Multidimensional Models - page 159

As usual, we test to see if the Sales Amount measure is zero or empty; if it is, there's
no point displaying a rank. Then, we take the set of all members on the same level
of the current member of the Products hierarchy, order that set by Sales Amount in
descending order, and return the rank of the CurrentMember inside that set.
Then, we can use the calculated member in reports like this: