oracle树结构数据类型sql

SELECT

DISTINCT CENT.*,LEVEL as lvl     

 FROM FSP_ETL.K3cloud_Erp_Cost_Center   CENT     

--从根节点开始，根节点id为0

START WITH CENT.Parent_Id = 0     

--可以理解为Source_Item_Id为id，Parent_Id为父节点id

CONNECT BY PRIOR CENT.Source_Item_Id =  CENT.Parent_Id     

ORDER BY CENT.Fu_Code