sql server 2008 - T-SQL CLR: Can you CREATE AGGREGATE with optional parameter(s)? -

i'm hoping able allow optional parameters specified, can overload accumulate() method, can done?

i'd overload allow delimiter specified, i've seen others must force delimiter specified behaviour doesn't suit.

create aggregate dbo.concatenate (@input nvarchar(max), <optional parameter here>) returns nvarchar(max) 

for reference, here aggregate class code contains accumulate() method i'm looking overload:

using system; using system.data; using microsoft.sqlserver.server; using system.data.sqltypes; using system.io; using system.text;   namespace clr.utilities {     /// <summary>     /// <list type="references">     ///     <reference>     ///         <name>how to: create , run clr sql server aggregate</name>     ///         <link>http://msdn.microsoft.com/en-us/library/91e6taax(v=vs.90).aspx</link>     ///     </reference>     ///     <reference>     ///         <name>sqluserdefinedaggregateattribute</name>     ///         <link>http://msdn.microsoft.com/en-us/library/microsoft.sqlserver.server.sqluserdefinedaggregateattribute(v=vs.90).aspx</link>     ///     </reference>     ///     <reference>     ///         <name>invoking clr user-defined aggregate functions (provides seed code function)</name>     ///         <link>http://technet.microsoft.com/en-us/library/ms131056.aspx</link>     ///     </reference>     /// </list>     /// </summary>     [serializable]     [sqluserdefinedaggregate(         format.userdefined,                 //use clr serialization serialize intermediate result         isinvarianttonulls = true,          //optimizer property         isinvarianttoduplicates = false,    //optimizer property         isinvarianttoorder = false,         //optimizer property         maxbytesize = -1)                   //no maximum size in bytes of persisted value     ]     public class concatenate : ibinaryserialize {         /// <summary>         /// variable holds intermediate result of concatenation         /// </summary>         private stringbuilder intermediateresult;          /// <summary>         /// initialize internal data structures         /// </summary>         public void init() {             this.intermediateresult = new stringbuilder();         }          /// <summary>         /// accumulate next value, not if value null         /// </summary>         /// <param name="value"></param>         public void accumulate([sqlfacet(maxsize = -1)] sqlstring value) {             if (value.isnull) {                 return;             }              this.intermediateresult.append(value.value.trim()).append(',');         }          /// <summary>         /// merge partially computed aggregate aggregate.         /// </summary>         /// <param name="other"></param>         public void merge(concatenate other) {             this.intermediateresult.append(other.intermediateresult);         }          /// <summary>         /// called @ end of aggregation, return results of aggregation.         /// </summary>         /// <returns></returns>         [return: sqlfacet(maxsize = -1)]         public sqlstring terminate() {             string output = string.empty;             //delete trailing comma, if             if (this.intermediateresult != null                 && this.intermediateresult.length > 0) {                 output = this.intermediateresult.tostring(0, this.intermediateresult.length - 1).trim();             }              return new sqlstring(output);         }          public void read(binaryreader r) {             intermediateresult = new stringbuilder(r.readstring());         }          public void write(binarywriter w) {             w.write(this.intermediateresult.tostring().trim());         }     } } 

and here code deployment i'd modify if optional parameters can set:

if  exists (select * sys.objects object_id = object_id(n'[dbo].[concatenate]') , type = n'af') drop aggregate [dbo].[concatenate] go  if  exists (select * sys.assemblies asms asms.name = n'clr.utilities' , is_user_defined = 1) drop assembly [clr.utilities] go  alter database [databasename] set trustworthy on go  create assembly [clr.utilities] 'c:\path\to\file\clr.utilities.dll' permission_set = unsafe go  create aggregate [dbo].[concatenate] (@input nvarchar(max)) returns nvarchar(max) external name [clr.utilities].[clr.utilities.concatenate] go  grant execute on [dbo].[concatenate] public go 

as far know, there's no way make clr function or aggregate optional parameters , that's sad.