spin thru the company table sorting breath first also in depth first.

Ch7_4.sql

WITH RSFC(CK,PK,LVL,HIER) AS
  (SELECT EMPLOYEE_ID,
    MANAGER_ID,
    0             AS LVL,
    EMPLOYEE_NAME AS HIER
  FROM COMPANY
  WHERE MANAGER_ID IS NULL
  UNION ALL
  SELECT EMPLOYEE_ID,
    MANAGER_ID,
    LVL+1,
    HIER
    || '/'
    || EMPLOYEE_NAME
  FROM RSFC R
  INNER JOIN COMPANY F
  ON R.CK = F.MANAGER_ID
  ) SEARCH BREADTH FIRST BY CK
  SET ORDR
--SEARCH DEPTH first by CK set ORDR
SELECT a.LVL,
  a.CK,
  a.PK,
  a.HIER,
  ORDR
FROM RSFC a
ORDER BY ORDR