MDX YTD over range (:) - mdx

Question

Does YTD can handle date range ?
I'm trying to compare a period of X days of the current year with the same period of the prior year.
My MDX query looks like this :
WITH MEMBER [Measures].[Prior YTD Amount] AS SUM
(
YTD
(
ParallelPeriod
(
[Date].[Year],
1,
[Date].CurrentMember
)
)
,
[Measures].[Amount]
)
set [ColSet] as
{
[Measures].[Amount],
[Measures].[Prior YTD Amount]
}
set [RowSet] as
{
[Motif].[Categorie].Members
}
SELECT
NON EMPTY [ColSet] ON COLUMNS,
NON EMPTY [RowSet] ON ROWS
FROM [Things]
WHERE
{
[Date].[2015].[2].[1]:[Date].[2015].[2].[9]
}
I'm working with Mondrian 3.6.

Answer 1

In short this code will not work. Reason being that the following line of code is looking for a single member of the hierarchy you've applied the Currentmember to:
[Date].CurrentMember
You have more than one member in the set [Date].[2015].[2].[1]:[Date].[2015].[2].[9]
Here is a small proof of the above:
This script:
WITH
MEMBER [Measures].[x] AS
[Date].[Calendar].CurrentMember.Member_Key
SELECT
{[Product].[Category].[All Products]} ON 0
,{[Measures].[x]} ON 1
FROM [Adventure Works]
WHERE
{
[Date].[Calendar].[Date].&[20080322]
};
Returns this:
Whereas this script:
WITH
MEMBER [Measures].[x] AS
[Date].[Calendar].CurrentMember.Member_Caption
SELECT
{[Product].[Category].[All Products]} ON 0
,{[Measures].[x]} ON 1
FROM [Adventure Works]
WHERE
{
[Date].[Calendar].[Date].&[20080322]
:
[Date].[Calendar].[Date].&[20080323]
};
Returns this:
Error message:
In AdvWrks I just wrote the following which might help, if you can move your target range of dates from the WHERE clause to a named set.
How it works:
1.Finds the first date in your named set via .Item(0).Item(0)
2.Finds the last date in your named set via .Item([myStartDates].Count - 1).Item(0)
3.The uses the two dates found to create a range that is parallel
WITH
SET [myStartDates] AS
{
[Date].[Calendar].[Date].&[20080322]
:
[Date].[Calendar].[Date].&[20080323]
}
SET [parallelToFirst] AS
ParallelPeriod
(
[Date].[Calendar].[Calendar Year]
,1
,[myStartDates].Item(0).Item(0)
)
SET [parallelToLast] AS
ParallelPeriod
(
[Date].[Calendar].[Calendar Year]
,1
,[myStartDates].Item(
[myStartDates].Count - 1).Item(0)
)
SET [Rebuild] AS
[parallelToFirst].Item(0) : [parallelToLast].Item(0)
SELECT
{} ON COLUMNS
,[Rebuild] ON ROWS
FROM [Adventure Works];
Easy enough to then Sum that range and pop it in the date dimension:
WITH
SET [myStartDates] AS
{
[Date].[Calendar].[Date].&[20080322]
:
[Date].[Calendar].[Date].&[20080323]
}
SET [parallelToFirst] AS
ParallelPeriod
(
[Date].[Calendar].[Calendar Year]
,1
,[myStartDates].Item(0).Item(0)
)
SET [parallelToLast] AS
ParallelPeriod
(
[Date].[Calendar].[Calendar Year]
,1
,[myStartDates].Item(
[myStartDates].Count - 1).Item(0)
)
SET [ParallelRange] AS
[parallelToFirst].Item(0) : [parallelToLast].Item(0)
MEMBER [Date].[Calendar].[parallelSum] AS
Sum([ParallelRange])
SELECT
{
[myStartDates]
,[ParallelRange]
,[Date].[Calendar].[parallelSum]
} ON 0
,{
[Measures].[Internet Sales Amount]
,[Measures].[Internet Order Quantity]
} ON 1
FROM [Adventure Works];
Here is the result (just to prove it is doing what we want):

Answer 2

Below is an alternative approach, to using ParallelPeriods function.
I am assuming you have all the dates from prev year in the cube, i.e. there are no missing dates in between or "gaps". If so, you can use the LAG function to hop over to the date 365 days(1 year) back. Also, have the dates from current year initially in a set. That way you can parametrize them easily.
Your final MDX should look somewhat similar to:
with set Dates as
{
[Date].[2015].[2].[1]
:
[Date].[2015].[2].[9]
}//<<This can be also written as
//StrToSet("{[Date]."+ #DateStart + ":" + "[Date]."+ #DateEnd + "}")
//#Date1 and #Date2 being the parameters you can pass from front end
set datesPrevYear as
{
head(Dates, 1).item(0).LAG(365).item(0) \\<<Gets the starting date's 1 year previous date
:
tail(Dates, 1).item(0).LAG(365).item(0) \\<<Gets the ending date's 1 year previous date
}
member [Measures].[Prior YTD Amount] as
sum(datesPrevYear, [Measures].[Amount])
set [ColSet] as
{
[Measures].[Amount],
[Measures].[Prior YTD Amount]
}
set [RowSet] as
{
[Motif].[Categorie].Members
}
select
non empty [ColSet] on columns,
non empty [RowSet] on rows
from [Things]