DAX ALLEXCEPT to sum by category of multiple dimension tables

Question

I would like to calculate total by category. The category is in the dimension table.

Here is sample file: DAX ALLEXCEPT total by category.pbix

I have the f

Answer 1

This is expected behaviour.

Power BI tables will include every row for which any measure in the table does not evaluate to BLANK().

ALLEXCEPT stops the values in the id and size columns from affecting the filter context when [Sales] is computed, and so every possible value for these two columns will give the same (non-blank) result (this causes the cartesian product that you see).

For example, on the (a, black, big) row, the filter context for the measures contains:

FactTable[id] = {"a"}
dim1[color] = {"black"}
dim2[size] = {"big"}

Then CALCULATE([Sales], ALLEXCEPT(...)) removes the FactTable[id] and dim2[size] from the filter context when evaluating [Sales]; so the new filter context is just:

dim1[color] = {"black"}

[Sales] in this filter context is not BLANK(), so the row is included in the result.

The proper way to fix this is to wrap the result in an IF, as you do in your Expected_Results_Color measure, or to add a filter on [Sales] not Blank to the table in Power BI.