Oracle Hierarchical query: how to follow max on each level

Question

I'm trying to get a query to "follow" the max values in each level excluding the max values in other branches.
Here some examples to illustrate what I'm trying to achieve:

Given this hierarchical structure:

 38
 15
 10
 5
 2
 3
 17
 9
 8
 6
 26
 13
 1
 12
 18
 11
 7

I would like to get:

 38
 17
 9

and not:

 38
 17
 10
 3

Like I would get by using the sql query I've come up with until now:

select lpad(' ',2*(level-1))|| max(child)
from test_connect_by 
start with parent is null
connect by prior child = parent
group by level

That get the absolute max from each level without excluding the other branches on each iteration over the levels.

The example data comes from http://www.adp-gmbh.ch/ora/sql/connect_by.html

Thanks in advance for any hint
Vlax

• ypercubeᵀᴹ: What if you used: select lpad(' ',2*(level-1)) || child from (select parent, max(child) as child from test_connect_by group by parent) t start with with parent is null connect by prior child = parent;
• Vlax: @ypercube that seems to be the answer to my woes, please put it as an answer so I can mark it as the correct answer. Thank you very much!

Answer 1

This seems to solve the question asked. Not sure if there is a solution without aggregating first:

select lpad(' ',2*(level-1)) || child as result
from 
 ( select parent, max(child) as child 
 from test_connect_by 
 group by parent
 ) t 
start with parent is null 
connect by prior child = parent
order by level ;