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
