CLR User-Defined Aggregates

Aggregate functions perform a calculation on a set of values and return a single value. Traditionally, Microsoft SQL Server has supported only built-in aggregate functions, such as SUM or MAX, that operate on a set of input scalar values and generate a single aggregate value from that set. SQL Server integration with the Microsoft .NET Framework common language runtime (CLR) now allows developers to create custom aggregate functions in managed code, and to make these functions accessible to Transact-SQL or other managed code.

The following table lists the topics in this section.

Topic	Description
Advantages of CLR User-Defined Aggregates	Describes the benefits of using CLR user-defined aggregate functions.
Requirements for CLR User-Defined Aggregates	Provides an overview of the requirements for implementing CLR user-defined aggregate functions.
CLR User-Defined Aggregate Properties Used by the Query Processor	Provides information about setting properties of a user-defined aggregate.
Invoking CLR User-Defined Aggregate Functions	Explains how to invoke user-defined aggregates.