Get second-highest element in hierarchy

Question

It's Friday afternoon and my brain isn't working well, and some of you people I'm sure will have the answer in a flash....
I have a typical hierarchical table, here's an example below;
with codes as
(select 17 icode,     -1 parent_code,'Group Services' descrip from dual
UNION
select 18,     -1,     'Counselling' from dual
UNION
select 20,     -1,     'Career Decision Making' from dual
UNION
select 21,     20,     'Career Assessment' from dual
UNION
select 22,     20,     'Academic Assessment' from dual
UNION
select 27,     22,     'Fee' from dual
UNION
select 28,     22,     'Transportation' from dual
UNION
select 33,     28,     'In-Province' from dual
UNION
select 34,     21,     'Fee' from dual
UNION
select 35,     21,     'Transportation' from dual
UNION
select 39,     35,     'Daily' from dual),
intervs as
(select 17 interv from dual
union select 18 interv from dual
union select 27 interv from dual
union select 33 interv from dual
union select 34 interv from dual
union select 39 interv from dual)
select interv,x.*
from intervs
INNER JOIN (select l1.icode k1,l1.descrip d1,
l2.icode k2 ,l2.descrip d2,
l3.icode k3 ,l3.descrip d3,
l4.icode k4,l4.descrip d4
from codes l4
left outer join codes l3 ON l3.icode = l4.parent_code
left outer join codes l2 ON l2.icode = l3.parent_code
left outer join codes l1 ON l1.icode = l2.parent_code)
x ON x.k4 = intervs.interv
What I would like to get for each intervs.interv is the k/d pair that is the second highest element in the hierarchy, or if there is no higher level in the hierarchy I'll take that.
So in the data that the above displays, I'd like 22 - academic assessment for #33,
21 Career Assessment for #34, and 18 and 17 would come back as themselves.
Thanks in advance,
Jon

Answer 1

or you can use the tradtional sql, it can run in most database
select * from scott.emp t11,
--get the second highest sal
select deptno, max(sal) sal
from
( --get the highest sal
select t1.deptno, t1.empno, t1.ename, t1.sal from scott.emp t1,
( select deptno,max(sal) max_sal
from scott.emp e
group by deptno
) t2
where t1.deptno=t2.deptno
and t1.sal<t2.max_sal
order by t1.deptno asc,sal desc
) t
group by t.deptno
order by t.deptno
) t22
where t11.deptno=t22.deptno
and t11.sal=t22.sal;