这个递归求和的sql应该怎么写？

怎么把子的AMOUNT汇总求和放到父上，最好可以用db2数据库实现。
当前数据：

img

想要的结果数据：

img

WITH T AS
(
  SELECT '01' AS ID, '一' AS NAME, '0' AS PID, '' AS AMOUNT, '001' AS XH FROM SYSIBM.DUAL UNION ALL
  SELECT '02' AS ID, '（一）' AS NAME, '01' AS PID, '' AS AMOUNT, '002' AS XH FROM SYSIBM.DUAL UNION ALL
  SELECT '03' AS ID, '（二）' AS NAME, '01' AS PID, '' AS AMOUNT, '006' AS XH FROM SYSIBM.DUAL UNION ALL
  SELECT '04' AS ID, 'A' AS NAME, '02' AS PID, '' AS AMOUNT, '003' AS XH FROM SYSIBM.DUAL UNION ALL
  SELECT '05' AS ID, 'B' AS NAME, '02' AS PID, '' AS AMOUNT, '007' AS XH FROM SYSIBM.DUAL UNION ALL
  SELECT '06' AS ID, 'A.1' AS NAME, '04' AS PID, '2' AS AMOUNT, '004' AS XH FROM SYSIBM.DUAL UNION ALL
  SELECT '07' AS ID, 'A.2' AS NAME, '04' AS PID, '3' AS AMOUNT, '005' AS XH FROM SYSIBM.DUAL UNION ALL
  SELECT '08' AS ID, 'B.1' AS NAME, '05' AS PID, '5' AS AMOUNT, '008' AS XH FROM SYSIBM.DUAL UNION ALL
  SELECT '09' AS ID, 'B.2' AS NAME, '05' AS PID, '6' AS AMOUNT, '009' AS XH FROM SYSIBM.DUAL UNION ALL
  SELECT '10' AS ID, 'B.3' AS NAME, '05' AS PID, '4' AS AMOUNT, '010' AS XH FROM SYSIBM.DUAL
)