[FIXED]
+ ---------------+ 
 
|PKEY |CKEY |NUM| 
| -----|-----|---| 
 
|AAA  |BBB  |  1  | 
|AAA  |CCC  |  5  | 
|AAA  |DDD  |  20 |
|CCC  |EEE  |  33 |
|DDD  |EEE  |  44 |
|DDD  |FFF  |  5  | 
|FFF  |GGG  |  5  | 
+ ---------------+
 

WITH PARENT (PKEY, CKEY) AS ANSWER
(SELECT PKEY, CKEY 
FROM HIERARCHY 
WHERE PKEY = ’AAA’ 
UNION ALL 
SELECT C.PKEY, C.CKEY
FROM HIERARCHY
,PARENT P 
WHERE P.CKEY = C.PKEY 
) 
SELECT PKEY, CKEY 
FROM PARENT;

ANSWER
ANSWER
========= PROCESSING
PKEY CKEY SEQUENCE
 ---- ---- ==========
 
AAA BBB  < 1st pass
AAA CCC   ""
AAA DDD  "  "
CCC EEE  < 2nd pass
DDD EEE  < 3rd pass
DDD FFF  " "
FFF GGG  < 4th pass
[/FIXED]