Perform drill across in MDX (SSRS) / joining two fact tables on one conformed dimension

Question

How can I join two fact tables in MDX by means of one conformed dimension?

For example (in SQL) I have 2 fact tables: shipment_facts, return_facts and one common dimension product, it would be:

 SELECT COALESCE (shp.product, rtn.product) as Product, quantity_returned / quantity_shipped as ReturnRate FROM ( SELECT product, sum(quantity_shipped)as quantity_shipped FROM shipment_facts, product WHERE ..... ) shp FULL OUTER JOIN ( SELECT product, sum(quantity_returned) as quantity_returned FROM return_facts, product WHERE.... ) rtn ON shp.product = rtn.product 

How can I implement this using MDX (or SSRS)?

Answer 1

This is handled automatically by Analysis Services if you query the cube. Just select the hierarchies you want on rows, and measures from any measure group (which is the Analysis Services construct derived from fact tables), and the results should be correct.

This just requires the cube design to be correct. In this context, this mainly means the configuration on the "Dimension Usage" tab of the Cube Editor in Business Intelligence Development Studio.