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