Tree checkboxes GetItem

CREATE PROCEDURE [dbo].[fm_tst-form-treeview_getItem]
    @itemID int,
    @username nvarchar(256)

AS
BEGIN
    select
      STUFF((SELECT ',' + cast(id as nvarchar)
      FROM tst_categories
      WHERE selected=1
      FOR XML PATH('')), 1, 1,'') f1  -- выделенные категории
END