多个消息接收者（数据库字段）

CREATE TABLE IF NOT EXISTS `inbox` (
  `id` int(11) NOT NULL auto_increment,
  `id_usuario` int(11) NOT NULL,
  `id_to` int(11) NOT NULL,
  `mensaje` varchar(250) collate utf8_spanish_ci NOT NULL,
  `texto` text collate utf8_spanish_ci NOT NULL,
  `fecha` date NOT NULL,
  `visto` int(1) NOT NULL,
  `adjunto` int(1) NOT NULL,
  `item` int(11) NOT NULL,
  PRIMARY KEY  (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_spanish_ci AUTO_INCREMENT=1 ;

\"select * from inbox where sesionid IN (idto)\"

\"select id_to from inbox where id = \'254\'\"