with t as (
           select  connect_by_root ename l1_ename,
                   lag(ename,2) over(order by 1) l2_ename,
                   prior ename l3_ename,
                   ename l4_ename,
                   level l
             from  emp
             start with mgr is null
             connect by mgr = prior empno
          )
select  l1_ename,
        l2_ename,
        l3_ename,
        l4_ename
  from  t
  where l = 4
/

L1_ENAME   L2_ENAME   L3_ENAME   L4_ENAME
---------- ---------- ---------- ----------
KING       JONES      SCOTT      ADAMS
KING       ADAMS      FORD       SMITH

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