select A.HOSPITAL_ID from T_HOSPITAL A connect by prior A.HOSPITAL_ID=A.PARENT_ID start with A.HOSPITAL_ID=1

select A.* from T_HOSPITAL A start with A.HOSPITAL_ID=9 connect by prior A.PARENT_ID=A.HOSPITAL_ID

一个是读取所有父标签，一个是读取所有子标签

字段里面只有parentId