Aggregation table - Diffrent agg levels for base table and agg table

Question

Is it possible to have Different aggregation level for base table and Aggregation. Say sum on a column in AGG table and Count for the same column in Fact table.
Example
Region,Day_product,sales person, customer are dimensions and Call is a fact measure
FACT_TABLE has columns Region, Day, Product, Sales person,Customer, Call
AGG_TABLE has columns Region, Month,Product, call
We already have a Logical Table definition for the fact table say FACT_CALL
We have a Logical column called No of customers.
For the Data source as FACT_TABLE Formula for the column is "Customer" and Aggregation level is count distinct.
But agg table we already have a calculated column call TOT_CUSTOMERS. which is been calculated and aggregated in the ETL.
IF we map this to the logical column we have to set the formula as TOT_CUSTOMERS and we need to define aggregation type as SUM as this is at REGION, MONTH AND Product level. But OBI does not allow to do so.
Is there a work around for this? Can you please let us know.
Regard
Arun D

Answer 1

The way BI server picks up the table that would satisfy the query is through column mappings and contents levels. You have set the column mappings to TOT_CUSTOMER, which is right. When it comes to aggregation, since its already precalculated through ETL, you want to set the aggregation to SUM. Which I would say - is not correct, you can set the aggregation to COUNT DISTIMCT which is same as that of the detailed fact. But set the content levels to month in date table, and appropriate levels in region etc., So now BI Server will be aware of how to aggregate the rows when it chooses the agg table.