WITH RECURSIVE org AS (
    SELECT id, manager_id, 1 AS lvl
    FROM employees
    WHERE manager_id IS NULL
    UNION ALL
    SELECT e.id, e.manager_id, o.lvl + 1
    FROM employees e
    JOIN org o ON e.manager_id = o.id
    WHERE o.lvl < 10          -- 深度上限
)
SELECT * FROM org;

WITH RECURSIVE walk AS (
    SELECT id, parent_id FROM nodes WHERE parent_id IS NULL
    UNION ALL
    SELECT n.id, n.parent_id
    FROM nodes n
    JOIN walk w ON n.parent_id = w.id
) CYCLE id SET is_cycle USING path
SELECT * FROM walk;