Oracle递归查询(树型查询)

prior放的左右位置决定了检索是自底向上还是自顶向下. 左边是自上而下（找子节点），右边是自下而上（找父节点）

SELECT T.AREA_CODE, T.AREA_NAME, T.AREA_LEVEL
  FROM TBL_SYS_AREA_CODE T
CONNECT BY PRIOR T.AREA_CODE = T.PARENT_AREA_CODE
 START WITH T.PARENT_AREA_CODE = '父级';

SELECT T.AREA_CODE, T.AREA_NAME, T.AREA_LEVEL
  FROM TBL_SYS_AREA_CODE T
CONNECT BY  T.AREA_CODE = PRIOR T.PARENT_AREA_CODE
 START WITH T.Area_Name = '子级'; 

 深入（转）：oracle 递归查询 CONNECT BY、START WITH、CONNECT_BY_ROOT、CONNECT_BY_ISLEAF、SYS_CONNECT_BY_PATH：https://blog.csdn.net/feier7501/article/details/21815691