mysql无限级分类表设计

1.先创建表

CREATE TABLE tdb_goods_types(
type_id SMALLINT UNSIGNED PRIMARY KEY AUTO_INCREMENT,
type_name VARCHAR(20) NOT NULL,
parent_id SMALLINT UNSIGNED NOT NULL DEFAULT 0
);

2.写入数据

INSERT tdb_goods_types(type_name,parent_id) VALUES(‘家用电器’,DEFAULT);
INSERT tdb_goods_types(type_name,parent_id) VALUES(‘电脑办公’,DEFAULT);
INSERT tdb_goods_types(type_name,parent_id) VALUES(‘大家电’,1);
INSERT tdb_goods_types(type_name,parent_id) VALUES(‘生活电器’,1);
INSERT tdb_goods_types(type_name,parent_id) VALUES(‘平板电视’,3);
INSERT tdb_goods_types(type_name,parent_id) VALUES(‘空调’,3);
INSERT tdb_goods_types(type_name,parent_id) VALUES(‘电风扇’,4);
INSERT tdb_goods_types(type_name,parent_id) VALUES(‘饮水机’,4);
INSERT tdb_goods_types(type_name,parent_id) VALUES(‘电脑整机’,2);
INSERT tdb_goods_types(type_name,parent_id) VALUES(‘电脑配件’,2);
INSERT tdb_goods_types(type_name,parent_id) VALUES(‘笔记本’,9);
INSERT td