area.sql.txt

学习sql练习使用CREATE TABLE IF NOT EXISTS `area` ( `id` int(11) unsigned NOT NULL, `pid` int(11) NOT NULL DEFAULT '0', `name` varchar(20) COLLATE utf8_unicode_ci NOT NULL DEFAULT '' ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci; 查询语句 select * from area a left join area b on a.id=b.pid