How to: Aggregate Data
An aggregation operation computes a single value from a collection of values. An example of an aggregation operation is calculating the average daily temperature from a month's worth of daily temperature values. This topic shows how to group orders by contact ID and get the average total due for each contact ID.
The same example is shown using LINQ to Entities and Entity SQL:
The example in this topic is based on the Adventure Works Sales Model. To run the code in this topic, you must have already added the Adventure Works Sales Model to your project and configured your project to use the Entity Framework. For more information, see How to: Use the Entity Data Model Wizard (Entity Framework) or How to: Manually Configure an Entity Framework Project and How to: Manually Define an Entity Data Model (Entity Framework).