Latest value for all members at a given point in time

We have a fact table with a current balance record. For this balance rows are added to the table only when the balance has changed. This way we can reduce the volume in the fact table by not saving redundant information for every point in time that we want to analyze.

In SQL it is a simple task to get a view of the lastest fact records for a given point in time. SELECT f1.* FROM factTable f1 WHERE f1.timestamp = (SELECT MAX(f2.timestamp) FROM factTable f2 WHERE f2.timestamp <= givenPointInTime AND f2.balanceKey = f1.balanceKey). In other words, the given point in time directly determines which rows should be fetched from our fact table, one row for each balance record (balanceKey). This row will of course include several dimension attributes, which represent the point in time when the balance changed.

Now, we would like to reproduce this behaviour in our Analysis Services 2005 cube. Using a time dimension, we would like to be able to select a given point in time and have the cube return all rows previous to that time, one row for each balanceKey. Not only the rows matching the given point in time. How can this be done? For the other dimension attributes, they should behave in a normal way, such that for the returned rows, you can slice using any combination of them.

Any help or ideas are appreciated,
Lars

Assuming that you're using AS 2005 Enterprise Edition, you could try the "Last Nonempty Child" aggregation:

http://msdn2.microsoft.com/en-us/library/ms175356.aspx

>>

SQL Server 2005 Books Online

Defining Semiadditive Behavior

Semiadditive measures, which do not uniformly aggregate across all dimensions, are very common in many business scenarios. Every cube that is based on snapshots of balances over time exhibits this problem. You can find these snapshots in applications dealing with securities, account balances, budgeting, human resources, insurance policies and claims, and many other business domains.

...

LastNonEmpty

The member value is evaluated as the value of its last child along the time dimension that contains data.

>>

|||

Thanks Deepak. We are on an Enterprise Edition (pre-SP1) but we do not get the desired behaviour using the "Last Nonempty Child" aggregation. In fact, it doesn't seem to make any difference at all from using SUM. We have created an example containing a relational database with a simple fact table and an analysis services database built upon it with a measure called "Account Balance". If we browse the cube and add the measure and the Account dimension to the results pane, then filter based on the Time dimension and select the date 2005-12-31, Account number 3 should display the balance 400. Currently it does not.

The example (SQL script + XMLA script) can be found at: http://www.intellibis.se/pub/CumulativeExample.zip

Can anyone help us?

Regards,
Lars

sql