FUNCTION TO concatenate all COLUMNS OF a TABLE

FUNCTION TO concatenate all COLUMNS OF a TABLE 

USE AdventureWorksDW2008
GO

CREATE FUNCTION fn_columns( @tblname varchar(50))
returns varchar(MAX)
as
BEGIN
DECLARE @name VARCHAR(500)=''
SELECT @name=name+', '+@name FROM SYS.columns WHERE OBJECT_ID=OBJECT_ID(@tblname)
RETURN left(@NAME,len(@NAME)-1)
END

 SELECT NAME,dbo.fn_columns(name)as COLUMNS from sys.tables