CURRENTMEMBER not covering a set of dates

Question

I have this script in MDX:

WITH 
MEMBER [Measures].[FirstDay] as
 HEAD (
  DESCENDANTS ( 
     [Date].[Date - Calendar Month].CURRENTMEMBER, 
     [Date].[Date - Calendar Month].[Calendar Day] )
  , 1
 ).ITEM( 0 ).member_value
MEMBER [Measures].[LastDay] as
 TAIL (
  DESCENDANTS ( 
     [Date].[Date - Calendar Month].CURRENTMEMBER, 
     [Date].[Date - Calendar Month].[Calendar Day] )
  , 1
 ).ITEM( 0 ).member_value
SELECT
  { 
   [Measures].[FirstDay], 
   [Measures].[LastDay] 
  }  ON COLUMNS
FROM [OurCube]
WHERE
  ({[Date].[Date - Calendar Month].[Calendar Year].&[2012], 
    [Date].[Date - Calendar Month].[Calendar Year].&[2013]})

Problem is that I'm trying to combine 2012 and 2013 in the WHERE clause as a set: this is then being used as the context for evaluation of the CURRENTMEMBER function in the custom measures - but this function expects a member and not a set.

How can I change the script so that it works returning 01 Jan 2012 and 31 Dec 2013 without including the dimension [Date] on either rows or columns ?

Answer 1

WITH 
MEMBER [Measures].[FirstDay] as
 (
  EXISTING  [Date].[Date - Calendar Month].[Calendar Day].Members
 ).ITEM( 0 ).member_value
MEMBER [Measures].[LastDay] as
 TAIL (
  EXISTING  [Date].[Date - Calendar Month].[Calendar Day].Members
  , 1
 ).ITEM( 0 ).member_value
SELECT
  { 
   [Measures].[FirstDay], 
   [Measures].[LastDay] 
  }  ON COLUMNS
FROM [OurCube]
WHERE
  ({[Date].[Date - Calendar Month].[Calendar Year].&[2012], 
    [Date].[Date - Calendar Month].[Calendar Year].&[2013]})

should deliver that. I simplified the first calculation a bit: as ITEM(0) already takes the first tuple, there is no need to use HEAD(..., 1).

See http://sqlblog.com/blogs/mosha/archive/2007/01/13/multiselect-friendly-mdx-for-calculations-looking-at-current-coordinate.aspx and the predecessor article referenced in the first sentence for some suggestions for "multiselect friendly MDX" from one of the developers of SSAS.