MDX query containing 2 dimensions from the same Hierarchy

Question

The relevant structures from my cube are that I have a Hierarchy with "Class" and "SubClass". I also have a Measure called "Value" which is what im trying to obtain.

A simple query may look like:

SELECT
 NON EMPTY ([Measures].[Value]) ON COLUMNS,
 NON EMPTY ([Some Dimension].[Class Hierarchy].[Class]) ON ROWS
FROM [MyCube]

And I can obviously read the SubClass using the HIerarchy which is returned to Adomd.

My issue is twofold, firstly how would I "flatten" this hierarchy so as to receive both Class and SubClass as discrete members in the CellSet? This does not work:

SELECT
 NON EMPTY ([Measures].[Value]) ON COLUMNS,
 NON EMPTY (
   [Some Dimension].[Class Hierarchy].[Class], 
   [Some Dimension].[Class Hierarchy].[Sub Class]
) ON ROWS
FROM [MyCube]

The Class Hierarchy hierarchy is used more than once in the Crossjoin function

Second issue, what I actuually need to do is filter the above on particular classes, again this wont work for the same reason as above.

SELECT
 NON EMPTY ([Measures].[Value]) ON COLUMNS,
 NON EMPTY (
   {[Some Dimension].[Class Hierarchy].[Class].&[ClassA],[Some Dimension].[Class Hierarchy].[Class].&[ClassB]}, 
   [Some Dimension].[Class Hierarchy].[Sub Class]
) ON ROWS
FROM [MyCube]

Any help much appreciated. MDX is driving me nuts!

Answer 1

You are missing the MEMBERS property on your dimension.

For your first example try this:

SELECT 
    NON EMPTY ([Measures].[Value]) ON COLUMNS,
    NON EMPTY {(
      [Some Dimension].[Class Hierarchy].[Class].MEMBERS,
      [Some Dimension].[Class Hierarchy].[Sub Class].MEMBERS)} ON ROWS
FROM [MyCube]

For your second example try this:

SELECT 
    NON EMPTY ([Measures].[Value]) ON COLUMNS, 
    NON EMPTY {(
      [Some Dimension].[Class Hierarchy].[Class].&[ClassA],
      [Some Dimension].[Class Hierarchy].[Class].&[ClassB],
      [Some Dimension].[Class Hierarchy].[Sub Class].MEMBERS)} ON ROWS
FROM [MyCube]