BEGIN
    declare @Output VARCHAR(255)
	Set @output=''
	Select @Output = case @Output
	                 WHEN '' then convert(varchar(255),cBTA )
			 ELSE @Output +  CONVERT (varchar(255),cBTA)
	                 END
 
FROM tblBTAPosDetails 
WHERE nAB=@nAB AND nPos=@nPos
Order by cBTA
	RETURN @Output
END