无限分类数据表（三级） 查看所有三级数据（面试题）

SELECT   c.one AS '一级分类' ,    C.`name` AS '二级分类' , D.`name` AS '三级分类' FROM  
( SELECT  A.`name` AS 'one', B.`name` , B.id AS 'id' FROM   tb_item_cat AS A   LEFT JOIN   tb_item_cat AS B  ON  B.parent_id=A.id ) AS C   
LEFT JOIN
tb_item_cat AS D 

ON D.parent_id=C.id