自定义列外连接查询语句

CREATE TABLE `test` (                                             `id` int(10) NOT NULL AUTO_INCREMENT,                           `name` varchar(255) NOT NULL,                                   `category_id` int(10) NOT NULL,                                 `date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,            PRIMARY KEY (`id`)                                            ) ENGINE=MyISAM AUTO_INCREMENT=6 DEFAULT CHARSET=utf8