CREATE TABLE news_class (
class_id int(10) unsigned NOT NULL default '0',
class_name char(50) NOT NULL default '',
class_top int(10) unsigned NOT NULL default '0',
class_num int(11) NOT NULL default '0',
class_top_id char(50) NOT NULL default '',
PRIMARY KEY (class_id)
) TYPE=MyISAM;


class_top是父类编号
class_num是层次
class_top_id是本类所有编号
INSERT INTO news_class VALUES (1, '体育新闻', 0, 1, '1');
INSERT INTO news_class VALUES (2, '财经新闻', 0, 1, '2');
INSERT INTO news_class VALUES (3, '国内体育', 1, 2, '1,3');
INSERT INTO news_class VALUES (4, '篮球消息', 1, 2, '1,4');
INSERT INTO news_class VALUES (5, '姚明', 4, 3, '1,4,5');
INSERT INTO news_class VALUES (7, '国内娱乐', 6, 2, '6,7');
INSERT INTO news_class VALUES (6, '娱乐新闻', 0, 1, '6');
INSERT INTO news_class VALUES (8, '王菲', 7, 3, '6,7,8');
INSERT INTO news_class VALUES (9, '自行车比赛', 3, 2, '1,3,9');