#查询所有的子
SELECT
*
FROM
t_resource t
WHERE
NOT EXISTS(
SELECT
1
FROM
t_resource t1,
t_resource t2
WHERE
t1.id= t2.parent_id
AND t1.id= t.id
) ;
#查询所有的父
SELECT
*
FROM
t_resource t
WHERE
NOT EXISTS(
SELECT
1
FROM
t_resource t1,
t_resource t2
WHERE
t1.id= t2.parent_id
AND t1.id= t.parent_id
) ;