Question

I am building a cube in SSAS that uses inventory movement data to show item activity. A sample of this data can be seen here (hopefully this is readable).

Date = Customer = Item = Receive Qty = Ship Qty = Movement

1/1/2000 = Cust123 = Item123 = 100 = 0 = 100

11/5/2011 = Cust123 = Item123 = 10 = 0 = 10

11/6/2011 = Cust123 = Item123 = 0 = -5 = -5

11/7/2011 = Cust123 = Item123 = 1 = 0 = 1

The goal is to include an opening balance in the cube. The opening balance for a given date is defined as the sum of all Movement (from the Movement field) for a given customer and item (my fact table contains many different customers and items) for all dates prior to the current date.

So in the sample data, the opening balance for the 11/6/2011 date would be the sum of all Movement (from the Movement field) where the customer and item are a match, and the date is less than 11/6/2011. Which would go all the way back to 1/1/2000 in my sample data.

Is there a way that MDX could help me accomplish this in my cube? I am relatively new to SSAS, but I believe there should be a way for me to include some MDX in the Calculations tab correct? Any help would be greatly appreciated. Thanks.

Answer 1

A quick dirty way would be:

sum({null:[Date].[Date Hierarchy].CurrentMember.Lag(1)}, [Measures].[Movement])

This assumes a few things:

1. Your CurrentMember of the Date Hierarchy will be at a day level.
2. Your dataset isn’t that big that this sum can be undertaken very quickly.

If you have a much larger dataset and this is slow for you, what you’ll want to do is to sum up the previous months (or years, depending on your partition level) first, and then do days of this month on top of it.