SSRS SQL 2008 R2: using Lookup to connect 2 AS datasets

Microsoft released a BI update to SQL Server 2008, aside from Gemini it has some other great new functions like the Lookup Function in reporting services. I was waiting for this one, you can lookup the first matching value for the specified name from a dataset that contains name/value pairs. This gives you the opportunity to join 2 datasets and whats best from 2 different cubes!

One mayor drawback is that you can only join on one key and a SSAS dataset usually doesn’t have a single key since you have data on an x and y axel, but with some custom work we can fix that.

In the following sample I have put data of 2 adventureworks datasets on one tablix. Each dataset contains year and Sales Territory Country and a measure. Lookup uses 2 keys to match the data from 2 datasets, I made a new unique key for each dataset combining the the uniquename of the x and y axel and added it as a calculated field to each dataset, added a field to each dataset with value “Fields!Sales_Territory_Country.UniqueName + Fields!Calendar_Year.UniqueName”.

Add the value of one dataset to a tablix

Then add a new column with the following expression to add the Internet_Order_Count value from the other dataset to the tablix:

=Lookup(Fields!CombKey.Value,Fields!CombKey2.Value,Fields!Internet_Order_Count.Value,”DataSet2″)

and thus adding the value from the 2nd dataset to the tablix, works like a charm. I even tested putting a filter on dataset 2 to make sure there aren’t an even amount of values and that works too, it just returns a null value.