mysql查询某节点的所有子节点，支持无限级

SELECT
	id ,parent_id,name
FROM
	(
	SELECT
		t1.id,t1.name,t1.parent_id,
	IF
		( find_in_set( parent_id, @pids ) > 0, @pids := concat( @pids, ',', id ), -1 ) AS ischild 
	FROM
		( SELECT id, parent_id,name FROM 表名 t) t1,
		( SELECT @pids := 需要查询的节点id ) t2 
	) t3 
WHERE
	ischild != -1
	

mysql查询某节点的所有父级节点，支持无限级

		SELECT
            t2.id,
            t2. category_parent_id as categoryParentId,
            t2.category_name as categoryName,
            t2.category_level as categoryLevel
        FROM
        (
                SELECT
                    @r AS _id,
                    (SELECT @r := category_parent_id FROM design_category WHERE id = _id) AS category_parent_id,
                    @l := @l + 1 AS lvl
                FROM (SELECT @r := 需要查询的节点id, @l := 0) vars, 表名 AS h
        ) t1 JOIN design_category t2 ON t1._id = t2.Id