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SQLCLR Overview

SQLCLR is a developer resource for SQL Server CLR integration — the engine feature that hosts the .NET Common Language Runtime inside SQL Server, letting you write database objects in C# (or any .NET language) instead of T-SQL.

The live site is at sqlclr.com.

What CLR integration gives you​

With CLR integration you can implement the following as compiled .NET code:

  • Scalar functions — string manipulation, regex, hashing, math that T-SQL handles poorly or slowly
  • Table-valued functions — stream rows from any .NET-accessible source
  • Stored procedures — procedural logic with real data structures
  • User-defined aggregates — custom aggregations (median, concatenation, statistical functions) that run in a single pass
  • User-defined types — structured values with behavior

When to use it (and when not to)​

CLR shines for compute-heavy, row-by-row work: parsing, regular expressions, custom aggregation, and algorithms that are awkward in set-based T-SQL. It is the wrong tool for ordinary data access — plain T-SQL almost always wins when the work is set-based.

Where to go next​

  • Quick Start — deploy your first CLR function in minutes
  • Installation — enable CLR integration properly
  • Core Concepts — assemblies, permission sets, and hosting
  • Security — signing, TRUSTWORTHY, and "CLR strict security"