select A.PARENT_GROUP_ID, A.GROUP_ID,sys_connect_by_path(A.GROUP_ID,'/') || '/' path from dam_dataentry_group A START WITH A.GROUP_ID in (select well_id from md_well)CONNECT BY PRIOR A.GROUP_ID = A.PARENT_GROUP_ID
使用到系统自带的函数:sys_connect_by_path