clr-user-defined-aggregates.md

title	CLR User-Defined Aggregates | Microsoft Docs
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ms.date	03/14/2017
ms.prod	sql-server-2016
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ms.technology	docset-sql-devref
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ms.topic	reference
helpviewer_keywords	aggregate functions [CLR integration] custom aggregates [CLR integration] calculations [CLR integration] user-defined functions [CLR integration]
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author	JennieHubbard
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manager	jhubbard

CLR User-Defined Aggregates

Aggregate functions perform a calculation on a set of values and return a single value. Traditionally, [!INCLUDEmsCoName] [!INCLUDEssNoVersion] 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. [!INCLUDEssNoVersion] integration with the [!INCLUDEmsCoName] .NET Framework common language runtime (CLR) now allows developers to create custom aggregate functions in managed code, and to make these functions accessible to [!INCLUDEtsql] or other managed code.

The following table lists the topics in this section.

Requirements for CLR User-Defined Aggregates
Provides an overview of the requirements for implementing CLR user-defined aggregate functions.

Invoking CLR User-Defined Aggregate Functions
Explains how to invoke user-defined aggregates.