Usage of "IN" clause issue in oracle 9i

Question

I HAVE QUERY
SELECT COUNT(*) FROM QUOTE WHERE OID IN (SELECT PARENT_ID FROM PARTY WHERE PARTY.COMPANY_ID = 1 AND PARTY.TYPE = 6)
Result returns zero rows. But there are 25000 rows in quote table with parent key of party table
WHEN I EXECUTE THE SAME AS
SELECT COUNT(*) FROM QUOTE WHERE OID IN (SELECT PARENT_ID FROM PARTY WHERE PARTY.COMPANY_ID = 1 AND PARTY.TYPE = 6
AND ROWNUM < 100000)
I AM ABLE TO GET THE RESULT.
MY QUESTION WHY IT NEED ROWNUM AND ALSO I FOUND IN 8i there is no such issue.
I AM FACING THE ABOVE ISSUE IN ORACLE 9i.
pl. let us know why and how it can be resolved.
Also i won't be able to use JOIN to resolVe this as
SELECT COUNT(*) FROM QUOTE, PARTY WHERE QUOTE.ID = PARTY.PARENT_ID AND PARTY.COMPANY_ID = 1 AND PARTY.TYPE = 6
will result duplicate.
pl do the needful. urgent

Answer 1

I don't know what is causing your error, but you have many options, including:
SELECT COUNT(*) FROM QUOTE Q
WHERE EXISTS (SELECT 1 FROM PARTY P WHERE P.COMPANY_ID=1 AND P.TYPE=6 AND P.PARENT_ID=Q.OID);
SELECT COUNT(DISTINCT QUOTE.ID) FROM QUOTE, PARTY WHERE QUOTE.ID = PARTY.PARENT_ID AND PARTY.COMPANY_ID = 1 AND PARTY.TYPE = 6;