Any reference to managed code from a Transact-SQL user-defined function counts as one ... cannot be included in the definition of a [!INCLUDE tsql] user-defined function: The following example uses ...

A user-defined function is a mechanism with which you can ... NAME '/common/math/exponent' LANGUAGE C PARAMETER STYLE DB2SQL NO SQL DETERMINISTIC NO EXTERNAL ACTION NOT FENCED In this example, the ...

Change a Transact-SQL function to a CLR function, or vice-versa. Requires ALTER permission on the function or on the schema. If the function specifies a user-defined type, requires EXECUTE permission ...

Now you can extract and parameterize your action logic and reuse it throughout your app, having only one source of truth for that logic that is easier to maintain. For more information and examples, ...

Although this falls naturally within the scope of relational databases, many such tasks cannot be expressed in SQL and require additional expressive power achieved via user-defined functions (UDFs).