Return Column as List of Comma Seperated Values

CREATE    PROCEDURE ap_ReturnCSV  
@SQLstring nvarchar(4000), @ColumnName varchar(25), @list varchar(8000)  OUTPUT 
/*********************************************************************************************************
       NAME: ap_ReturnCSVSpecified by: Bryan Bain
       REQUESTED DATE: 14-OCT-2003Designed by:  Bryan Bain
Bryan@HillCountryVillage.com

Requirements:Returns a comma seperated string of a single column from a select statement

Parameters:@SQLstring = The complete SELECT statement used to get the column rows
@ColumnName = The name of the column to use (this would also be in @SQLstring)
@list = the returned string of comma seperated values
Example: 
--Get CSV list of warehouses 
USE PUBS
declare @SQLstring nvarchar(4000), @ColumnName varchar(25), @list varchar(8000)
SET @SQLstring = 'SELECT * FROM employee'


SET @ColumnName = 'emp_id'

EXEC ap_ReturnCSV @SQLstring, @ColumnName, @list OUTPUT

print @list


REVISION:   REVISIONDATE    ACTION
--------    ------------        ------
**********************************************************************************************************/

AS  


BEGIN 
   DECLARE @newSQL nvarchar(4000)


   SET @newSQL = 'SELECT DISTINCT CONVERT(varchar(25),' + @ColumnName + ') ' +
RIGHT(@SQLstring,(LEN(@SQLstring)-CHARINDEX ('FROM' , @SQLstring))+1)


--convert UIDs to string of comma seperated values

CREATE TABLE #workingtable 
(
i int IDENTITY (1, 1) NOT NULL ,
vc varchar (10),
) 

insert into #workingtable (vc) EXECUTE sp_executesql @newSQL


declare
    @lasti int

select
    @list = '',
    @lasti = 1
update
    #workingtable
set @list = 
   case
                       when @lasti = i then vc
                       else @list + ',' + vc
                   end,
         @lasti = i

   

END