using System; 
using System.Collections.Generic; 
using System.Data.SqlTypes; 
using System.Linq; 
using System.Text; 
namespace TEST 
{ 
  public class TestTrans 
  { 
    [Microsoft.SqlServer.Server.SqlFunction] 
    public static SqlString GenerateDecryptString(string name) 
    { 
      string decode = string.Empty; 
      decode = string.Format("HELLO WORLD {0}!", name);//DecryptString(dataXML.Value); 
      SqlString sqlValue = new SqlString(decode); 
      return sqlValue; 
    } 
  } 
} 

 exec sp_configure 'clr enabled',1  
 reconfigure  
 Go

CREATE ASSEMBLY testHelloWorld FROM 'C:\TEST.dll'   --('C:/TEST.dll'w为错误写法)

CREATE FUNCTION dbo.clrHelloWorld   
(   
  @name as nvarchar(200)   
)   
RETURNS nvarchar(200)  
 AS EXTERNAL NAME testHelloWorld.[TEST.TestTrans].GenerateDecryptString  

SELECT dbo.clrHelloWorld('耿耿')