I'm using SQL Server Reporting Services. Most of my queries run as reports which are simply exported as PDF.
I'd like to know which type of calculations, if any, should done in the actual SQL query and which should be calculated using the SSRS IDE (Business Intelligence Studio).
For example, if I have a 12 month sales report (12 months) which requires a sales average of the 3 most recent months, where should that average be calculated?
Should most calculations/aggregations be done in the presentation layer? Any exceptions?