sql中根据父节点获取所有的子节点语句

WITH sub_nodes(pk_id) AS (
    SELECT pk_id FROM IBP_T_Regions WHERE iparentid = 56
    UNION ALL
    SELECT tn.pk_id FROM IBP_T_Regions tn
    JOIN IBP_T_Regions s ON tn.iparentid = s.pk_id
)
SELECT * FROM sub_nodes;

如果修改指定父节点所有子节点的部门id值如下：

WITH sub_nodes(pk_id) AS (
    SELECT pk_id FROM IBP_T_Regions WHERE iparentid = 1
    UNION ALL
    SELECT tn.pk_id FROM IBP_T_Regions tn
    JOIN sub_nodes s ON tn.iparentid = s.pk_id)
    select * from sub_nodes
update IBP_T_Regions set iDeptid=159 from sub_nodes pt where IBP_T_Regions.PK_ID=pt.PK_ID