Oracle taking a strange query execution path

Question

I have a query which is admittedly a bit unconventional but Oracle is really doing something strange with it...
SELECT   GROUP_CODE, STATUS, COL3, COL4, ETC...
FROM MAIN_TABLE A
WHERE A.STATUS = 'COMPLETE' -- ONLY GET COMPLETE RECORDS...
    -- AND ONLY FOR THOSE WHERE THERE ARE NO INCOMPLETE RECORDS IN THE SAME GROUP
    AND (SELECT COUNT(*) FROM MAIN_TABLE B WHERE B.GROUP_CODE = A.GROUP_CODE AND B.STATUS != 'COMPLETE') = 0
ORDER BY GROUP_CODE  
[\CODE]
This query is done on a table of ~100k records, and the result should only return about 100 or so records.
The only index in the table is on GROUP_CODE, and statistics are up-to-date.
The strange part is that the query takes over an hour to complete, UNLESS I take out the ORDER BY, then it takes only a few seconds!!!  The difference is that with the ORDER BY, it is using the GROUP_CODE index (even with a */*+ NO_INDEX(MAIN_TABLE) */* hint in the query).
How can I either reorganize this query or prevent Oracle from taking the "incorrect" path?
Edited by: xaeryan on May 20, 2011 3:01 PM
Edited by: xaeryan on May 20, 2011 3:02 PM                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           

Answer 1

try something as below..
select *
from
     select GROUP_CODE, STATUS, COL3, COL4, ETC...,
     max(case when STATUS != 'COMPLETE' then 1 ELSE 0 END) over( partition by  GROUP_CODE) as mx
     from
     MAIN_TABLE
)X
where mx= 0 HTH...