MDX for Start of Month Values at Daily level

Question

Hey Guys,
I am dealing with a requirement as below, the solution i have is either not addressing the complete problem or is extremely slow and in many cases just not feasible. Need a little help on the same.
Problem: Need a query with cross join of 4 dimension (10 levels) and a date dimension, i need to determine a measures's first
available value across time periods such as Start of month, start of year Etc.. 
I have 
dimA - Level A1
dimB - Leve B1,B2,B3
dimC - Level C1
dimD - LevelD1, D2,D3,D4,D5
Date Dimension - Date, Month, Year as levels.
Measure - M1 To M5
Query: 
SELECT
NON EMPTY
[Measures].[M1]
,[Measures].[M2]
,[Measures].[M3]
,[Measures].[M4]
,[Measures].[M5]
,[Measures].[M1SOM]
} ON COLUMNS
,NON EMPTY
[DimA].[A1].[A1].ALLMEMBERS*
[DIMB].[B1].[B1].ALLMEMBERS*
[DIMB].[B2].[B2].ALLMEMBERS*
[DIMB].[B3].[B3].ALLMEMBERS*
[DIMB].[B4].[B4].ALLMEMBERS*
[DIMB].[B5].[B5].ALLMEMBERS*
[DIMC].[C1].[C1].ALLMEMBERS*
[DIMD].[D1].[D1].ALLMEMBERS*
[DIMD].[D2].[D2].ALLMEMBERS*
[DIMD].[D3].[D3].ALLMEMBERS*
[Date].[Date].[Date].ALLMEMBERS*
[Date].[Month].[Month].ALLMEMBERS*
} ON ROWS
FROM
[Cube]
***The above query has all those cross joins as this query would power an SSRS report dataset.
Need to create a new calculated measure or a real (persisted measure) that displays the Start of month & Start of year Values. Below are the options i have currently. Lets assume, Measure M1 is the one for which i need the SOM and SOY values.
Create a persisted measure (M1SOM) based off the measure M1 and provide an aggregation function of "FirstNonEmpty" : This works perfectly when we run a query at Month level i.e. in the above query have [Date].[Month].[Month].Allmembers instead
of [Date].[Date].[Date].Allmembers. It displays the first available non empty value of the month. However, this means the rest of the measures are aggregated at month level. If i want to display the daily values of the other measures along with SOM values
for this measure it wont work, cause the scope now changes to a single date and i just get the daily value in the M1SOM measure as well.
Create a calculated measure (M1SOM) as below, along with the query above and the same thing happens. Cant display the SOM values at a daily date level.
WITH
MEMBER [Measures].[M1SOM] AS
[Date].[Date].FirstChild
,[Measures].[M1]
3. Create a calculated member as below, This works! however, the query
absolutely kills my machine and takes forever to execute, if i run it with more than 3 levels in the cross join. 
WITH MEMBER M1SOM AS Head(NonEmpty({[Date].[Date].Parent.Children}*[Measures].[M1SOM])).Item(0)
Is there a better way to achieve the SOM and SOY calculations at a daily level?
Thanks
Srikanth

Answer 1

Hi Srikanth,
Basically you want to get the cell values on different granularity for date dimension in the same result set. For performance consideration, we suggest to use MDX to get the 2 types of value separatedly and merge with T-SQL.
Below is an example on how to get data from MDX within T-SQL for your reference.
SET
@mdx
=
'{some
dynamic MDX}' 
SET @sql
=
'SELECT a.* FROM
OpenQuery(LinkedAnalysisServer, '''
+
@mdx
+
AS a' 
BEGIN TRY 
INSERT INTO #result 
EXEC sp_executesql @sql 
END TRY 
BEGIN CATCH 
  IF ERROR_NUMBER <>
'The error number you are seeing' 
  BEGIN 
    RAISERROR('Something happened that was not an empty result set') 
  END 
END CATCH 
SELECT * FROM
#result 
Regards