MDX: Aggregates over a set - mdx

Question

What I am trying to achieves looks very simple, yet I cannot make it work.
My facts are orders which have a date and I have a typical time dimension with the 'Month" and 'Year' levels.
I would like to get an output which lists the number of orders for the last 6 months and the total, like this:
Oct 2009 20
Nov 2009 30
Dec 2009 25
Jan 2009 15
Feb 2010 45
Mar 2010 5
Total 140
I can create the set with the members Oct 2009 until Mar 2010 and I manage to get this part of my desired output:
Oct 2009 20
Nov 2009 30
Dec 2009 25
Jan 2009 15
Feb 2010 45
Mar 2010 5
Just I fail to get the total line.

Answer 1

You can achieve this by adding the ALL member to the set and then wrapping it all in the VisualTotals() function
SELECT
... on COLUMNS,
VISUALTOTALS (
{[Month].[Month].[Oct 2009]:[Month].[Month].[Mar 2010]
, [Month].[Month].[All] }
) ON ROWS
FROM <cube>

Answer 2

here is one possible solution for Adventure Works DW Demo Cube. The query selects the last 6 Order Counts and add a sum on the date dimension:
WITH MEMBER [Date].[Calendar].[Last 6 Mth Order Count] AS
aggregate(
ClosingPeriod([Date].[Calendar].[Month], [Date].[Calendar].[All Periods]).Lag(6)
: ClosingPeriod([Date].[Calendar].[Month], [Date].[Calendar].[All Periods])
)
SELECT {[Measures].[Order Count]} ON COLUMNS
, {ClosingPeriod([Date].[Calendar].[Month], [Date].[Calendar].[All Periods]).Lag(6)
: ClosingPeriod([Date].[Calendar].[Month], [Date].[Calendar].[All Periods])
,[Date].[Calendar].[Last 6 Mth Order Count]}
ON ROWS
FROM [Adventure Works]