Using calculated member as parameter in MDX function

Question

I'm new to MDX but want to keep my code as clean as possible.

I have a query that looks at todays sales and compares them against LY and LY-1 using the ParallelPeriod function. It looks something like this..

With Member [Date].[SalesCalendar].[DateToday] as [Date].[SalesCalendar].[Date].&[2012-10-26T00:00:00]

SELECT 

    {[Date].[SalesCalendar].[DateToday],

    ParallelPeriod([Date].[SalesCalendar].[Year],1,[Date].[SalesCalendar].[Date].&[2012-10-26T00:00:00]),

    ParallelPeriod([Date].[SalesCalendar].[Year],2,[Date].[SalesCalendar].[DateToday]}

    *  

    {[Measures].[Total Sales],[Measures].[Units],[Measures].[Sales Target]}
    ON Columns,

    [Locations].[Location PK].[Location PK]
    on Rows

From MyCube

I start by defining a member that points to today's date. I want to define it once and use it throughout this query (and other queries I write), the theory being I can change it in once place and the underlying query reacts.

The problem I have is that if I try and use this calculated member within the ParallelPeriod function I get no results. With the query above I get results for the first column and the first call to ParallelPeriod (for LY) works but the second call for LY-1, which uses the declared member, fails.

I'm guessing this is down to my lack of knowledge with MDX and so I guess I am missing something fundamental. However, banging my head against the wall isn't working so I need some help!

Any ideas what I am doing wrong?

Thanks

Answer 1

This cannot work because when your query is evaluated [Date].[SalesCalendar].[DateToday] is not replaced with [Date].[SalesCalendar].[Date].&[2012-10-26T00:00:00] .

You created a member that will give the same numeric values than [Date].[SalesCalendar].[Date].&[2012-10-26T00:00:00] in the pivot table cells.

You can try this query:

With Member [Date].[SalesCalendar].[DateToday] as [Date].[SalesCalendar].[Date].&[2012-10-26T00:00:00]
     Member [Measures].[name] as [Date].[SalesCalendar].CurrentMember.Name

SELECT 
    {[Measures].[name], [Measures].[Total Sales]} ON Columns,
    {[Date].[SalesCalendar].[DateToday], [Date].[SalesCalendar].[Date].&[2012-10-26T00:00:00]} on Rows
From MyCube

The Total Sales will be the same but not [Measures].[name] .