Create a new table with distinct values

Hi

I am trying to create a new distinct table.

My source data has the following fields:

Store ID, Department, Month, Total Sales

I need understand how I can create a table which will display the Departments as a distinct list with the number of stores per Department.

Department EG: Retail, 4 Stores

This table needs to be dynamic and only show active stores in the data source.

Thanks

Dale