postgres递归查询所有子部门

WITH RECURSIVE T ( ID, parent_id,depart_name ) AS (
            SELECT
                A.ID,
                A.parent_id,
                a.depart_name
            FROM
                sys_depart A
            WHERE
                A.id = 'bcb9dc287fbe40178162a6f9c877f3ef' UNION ALL
            SELECT
                b.ID,
                b.parent_id ,
                b.depart_name
            FROM
                sys_depart b,
            T
            WHERE
                b.parent_id = T.id
            ) SELECT ID, parent_id as "pId",depart_name as "text" FROM T

 WITH RECURSIVE r AS (
SELECT * FROM test1 as t WHERE m_id = 18
union ALL
SELECT t.* FROM trade.merchant as t, r WHERE tree.par = r.m_id
)
SELECT * FROM r where stat = 1 ORDER BY m_id
它会一直递归调bai用，直到没有记录返回。
第一步，du会得到 SELECT * FROM test1 as t WHERE m_id = 18 ，一条记录。zhi并放在R中
然后再执行 SELECT t.* FROM trade.merchant as t, r WHERE tree.par = r.m_id 放入R中。 之后不断dao循环这一步。