MDX query containing 2 dimensions from the same Hierarchy - mdx

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]

Answer 2

Use Subqueries in your WHERE Clause.
MDX will always restrict the use of one dimension on one Axis only.
Sub Query is a way to get around that. I recently learnt this trick after MDX drove me nuts as well..

Answer 3

Hi this query worked for me.
SELECT NON EMPTY { [Measures].[App Count] }
ON COLUMNS,
NON EMPTY
{(
EXISTING
(
[MART TIME DIM].[Date].[Date] .MEMBERS) *
[New Ren DIM].[New Ren CODE].[New Ren CODE].ALLMEMBERS
)}
ON ROWS FROM [SubmissionCube]
where
({
[MART BROKER DIM].[BROKER ID].&[10812]},{[MART TIME DIM].[Year].&[2015],
{[MARTTIME DIM].[Year].&[2016]}
})
Please be carefull with the '}' in the where clause as the query has.