Microsoft® SQL Server 2012 Unleashed

Data Planning and Preparation

The first step in report development is to prepare your data for use with SSRS. Generally speaking, when you are working with non-file data, this means creating the T-SQL tables, views, procedures, and functions from which your data sources will retrieve rows. Any complex logic required to get to report data should happen within the Database Engine, not within SSRS.

The rule of thumb is to keep complex logic and intricate calculations out of your reports and to prepare them ahead of time in your sources. A good reason to put this policy into practice is that, from a maintenance perspective, it will be much easier for you and your colleagues to modify a report if all that is necessary is to change the underlying T-SQL. ...