How to expose total number of days in each month via OLAP cube - sql-server-2012

Question

I'd like an easy way of getting the total number of days for each month in the date dimension.
Currently this information is not exposed in our cubes. Therefore I need to write custom mdx such as the following:
WITH
SET [13Mth] AS Tail([Date].[Date - Calendar Month].[Calendar Month].MEMBERS ,13)
SET [m] AS Tail([13Mth])
MEMBER [Measures].[TotalNumDaysMth] AS
Datepart
("D",
Dateadd
("M",1,
Cdate(Cstr(VBA!Month([m].Item(0).Item(0).Lag(1).Name)) + "-01-" + Cstr(VBA!Year([m].Item(0).Item(0).Lag(1).Name)))
)
- 1
)
MEMBER [Measures].[TotalNumDaysMth-1] AS
Datepart
("D",
Dateadd
("M",1,
Cdate(Cstr(VBA!Month([m].Item(0).Item(0).Lag(1).Name)) + "-01-" + Cstr(VBA!Year([m].Item(0).Item(0).Lag(1).Name)))
)
- 1
)
I don't believe our users will need this information within our cube browsing client but from a developer point of view I could do without having to always implement the above.
What approach should we use to make the above data more easily available?

Answer 1

I have always added an attribute to the date dimension "days in month", of type integer. You can hide this attribute, if you do not want to expose the attribute hierarchy to your users.
But you can still use in calculations.
So my advise would be add a proper attribute to your time dimension and base your calculations of on the attributes.
Hope this helps somehow.

Answer 2

I am assuming that in your development scenario, the month will come from Web Service/Front End/SSRS report etc. In any such cases, you can create a measure that will return the count.
Approach 1: Year-Quarter-Month-Date exists
It is a good practice to have a similar hierarchy in place. The following MDX will work:
with set CurrentMonth as
[Date].[Year-Quarter-Month-Date].currentmember
set DatesInCurrentMonth as
descendants(abc, [Date].[Year-Quarter-Month-Date].[Date])
member [Measures].countofdaysinmonth as
count(DatesInCurrentMonth)
select measures.CountOfDaysInMonth on 0
from [MyCube]
where [Date].[Year-Quarter-Month-Date].[Month].&[Feb-2004]
Approach 2: Such hierarchy doesn't exist
with set CurrentMonth as
[Date].[Month].currentmember
set DatesInCurrentMonth as
exists([Date].[Date].children, abc, "<<Any Measure group>>")
member measures.countofdaysinmonth as
count(DatesInCurrentMonth)
select measures.countofdaysinmonth on 0
from [MyCube]
where [Accident Date].[Month].&[Feb-2004]
Let me know if they work/have issues.