WHERE IN () v poddotazu nevrací všechny řádky

CREATE TABLE IF NOT EXISTS `article` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `t2_in` varchar(200) CHARACTER SET latin1 NOT NULL,
  `title` varchar(200) DEFAULT NULL,
  `text` varchar(200) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 AUTO_INCREMENT=3 ;

INSERT INTO `article` (`id`, `t2_in`, `title`, `text`) VALUES
(1, '1,2,3', 'titulek 1', 'text1...'),
(2, '1,4', 'titulek 2', ' text2...');

CREATE TABLE IF NOT EXISTS `tag` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(800) CHARACTER SET utf8 COLLATE utf8_czech_ci NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 AUTO_INCREMENT=5 ;

INSERT INTO `tag` (`id`, `name`) VALUES
(1, 'první'),
(2, 'druhý'),
(3, 'třetí'),
(4, 'čtvrtý');

SELECT *, (SELECT GROUP_CONCAT(tag.name) FROM tag  WHERE id IN (article.t2_in) ) FROM article

SELECT *, (SELECT GROUP_CONCAT(tag.name) FROM tag  WHERE id IN (1,2,3) ) FROM article

SELECT *, (SELECT GROUP_CONCAT(tag.name) FROM tag  WHERE id = 1 OR id = 2 OR id = 3 )

SELECT *, (SELECT GROUP_CONCAT(tag.name) FROM tag  WHERE id = nejaky_jiny_sloupec )