start with connect by prior,该怎么解决

 SELECT CBD.ID,
                                                        level levels,
                                                         (CASE WHEN LEAD(level) OVER(ORDER BY rowNum) > level THEN '1' ELSE '0' END) isLeaf
                                                  FROM PRODUCT_TYPE CBD
                                                       where CBD.company_id  is null or CBD.company_id='C4FCAEEF63ED9F03E040860A50826BB5'
                                                       START WITH CBD.ID ='C4FE7B67ED2877A3E040860A5082732F'
                                                       CONNECT BY PRIOR CBD.ID = CBD.PRODUCT_PARENT_TYPE 
                                                   )typeTree
                                                   WHERE  1=1 and typeTree.levels =(