SELECT
dept_id
FROM
sys_dept
WHERE
dept_id = ${dept_id}
UNION
(
SELECT
dept_id
FROM
(
SELECT
t1.dept_id,
IF (
find_in_set(parent_id, @pids) > 0,
@pids := concat(@pids, ',', dept_id),
0
) AS ischild
FROM
(
SELECT
dept_id,
parent_id,
dept_name
FROM
sys_dept t
WHERE
1 = 1
ORDER BY
parent_id,
dept_id
) t1,
(
SELECT
@pids := ${dept_id} /**要查询的菜单节点 id**/
) t2
) t3
WHERE
ischild != 0
)