Nesting with columns named id and parent_id

Create table mytable :

CREATE TABLE IF NOT EXISTS `mytable` (
  `id` int(11) NOT NULL,
  `parent_id` int(11) NOT NULL,
  `name` varchar(256) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

--
-- Dumping data for table `mytable`
--

INSERT INTO `mytable` (`id`, `parent_id`, `name`) VALUES
(1, 0, 'item 1'),
(2, 1, 'item 2'),
(3, 2, 'item 3');

And then run following script