A[01,16]
B[02,03]    C[04,13]    H[14,15]
            D[05,12]
            E[06,07]    F[08,11]
                        G[09,10]

<A>content A<B>content B</B><c>content C<C>content D<E>content E</E><F>content F<G>content G</G></F></D></C><H>content H</H></A>

CREATE TABLE IF NOT EXISTS `tree` (
  `id` int(11) NOT NULL,
  `tag` varchar(100) NOT NULL,
  `lft` int(11) NOT NULL,
  `rgt` int(11) NOT NULL,
  `desc` text NOT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1;


INSERT INTO `tree` (`id`, `tag`, `lft`, `rgt`, `desc`) VALUES
(1, 'A', 1, 16, 'content A'),
(2, 'B', 2, 3, 'content B'),
(3, 'C', 4, 13, 'content C'),
(4, 'D', 5, 12, 'content D'),
(5, 'E', 6, 7, 'content E'),
(6, 'F', 8, 11, 'content F'),
(7, 'G', 9, 10, 'content G'),
(8, 'H', 14, 15, 'content H');