Querying Hierarchy - Above + Below

Question

Hi,
I have the following situation:
I have a table HIERARCHY with the following fields:
<PRE>
CHILD PARENT          
===================
100               
101 100          
102 101          
103 102          
104
105 100          
106 105          
This is what I need :
CHILD     PARENT     PATH      LEVEL
=============================
100 100 1
101 100 100/101 2
102 101 100/101/102 3
103 102 100/101/102/103 4
104 104 1
105 100 100/105 2
106 105 105/106 2
Now, the important part is when I query on the above result for example "WHERE CHILD = 102", I should get the whole hierarchy (above + below).
So the result would look like ...
CHILD     PARENT     PATH      LEVEL
=============================
100 100 1
101 100 100/101 2
102 101 100/101/102 3
103 102 100/101/102/103 4
</PRE>
Any idea how this can be achieved via SQL query....
Thanks in Advance.
Regards
Pat

Answer 1

Hi, Pat,
It sounds like you want a to do a CONNECT BY query on the resuot set of a UNION of 2 CONNECT BY queries
(1) a bottom-up query, of the ancestors of the target row
(2) a top-down query, of the descendants of the target row
WITH  universe  AS
    SELECT   child, parent
    FROM    hierarchy
    START WITH  child = :target_child
    CONNECT BY  child = PRIOR parent
        -- Bottom-up part (for target and its ancestors) is above
    UNION
        -- Top-down part (for descendants) is below
    SELECT  child, parent
    FROM    hierarchy
    START WITH  parent = :target_child
    CONNECT BY    parent = PRIOR child
SELECT  child
,       parent
,       LTRIM (SYS_CONNECT_BY_PATH (child, '/'), '/')  AS path
,       LEVEL
FROM    universe
START WITH  parent IS NULL
CONNECT BY  parent = PRIOR child
;I hope this answers your question.
If not, post a little sample data (CREATE TABLE and INSERT statements) and the results you want from that data (if they are not the results you already posted).
Always mention your version of Oracle.