SQL subselect, group by, sum equivalent in MDX(SSAS) - ssas

Question

I have a problem with creation of calculated member in SSAS.
Fact table:
Date Store Product Sales_in_USD
--------------------------------------------------
2016-07-01 Store1 Product1 50
2016-07-01 Store1 Product2 100
2016-07-01 Store2 Product3 70
2016-07-01 Store2 Product2 85
Dimensions:
Dates,Stores,Products
I want to get something like that:
If I filter by some product I want to get all sales by this store and date that include sales by filtered product+another products, for example I want filter by Product1:
SQL code:
select sum(Sales_in_USD)
from [Fact table]
where Store in (select Store from [Fact table] where Product="Product1")
Executing this sql code I get all Sales by Store1.
How I can create it with MDX when I want create a calculated member?
Output of calculated member must be the next:
Product Total_Sales_By_Store
------------------------------
Product1 50+100=150
Product2 50+100+70+85=305
Product3 70+85=155

Answer 1

1 - Determine the valid stores for the selected product.
NonEmpty(
[Store].[Store Name].MEMBERS,
([Product].[Product].Currentmember,[Measures].[Sales_in_USD])
)
2 - Once you have the stores for the current product, you want to calculate the sum of values for the possible tuples(cross join).
with member Measures.[Total Sum of Stores] as
sum(
[Product].[Product].Currentmember *
NonEmpty
(
[Store].[Store Name].MEMBERS,
([Product].[Product].Currentmember,[Measures].[Sales_in_USD])
)
,
[Measures].[Sales_in_USD]
)
select Measures.[Total Sum of Stores] on 0
from [YourCube]
where [Product].[Product].[Product1]

Answer 2

SELECT
[Measures].[Sales_in_USD] ON 0,
{[Store].[Store Name].MEMBERS,
[Product].[Product].MEMBERS} ON 1
FROM [Cube Name];
For your requirement, you really don't need a calculated member, since the measures will do the job for you
For Particular Product Name Product1, then
SELECT
[Measures].[Sales_in_USD] ON 0,
{[Product].[Product].&[Product1],
[Store].[Store Name].MEMBERS
} ON 1
FROM [Cube Name];

Answer 3

I think Sourav has pretty much nailed it but it could be more general?
WITH
MEMBER [Measures].[Total Sum of Stores] AS
SUM(
NONEMPTY(
[Store].[Store Name].MEMBERS,
(
[Product].[Product].Currentmember
,[Measures].[Sales_in_USD]
)
)
,[Measures].[Sales_in_USD]
)
SELECT
[Measures].[Total Sum of Stores] on 0,
[Product].[Product].[Product].MEMBERS ON 1
FROM [YourCube];