Issue on left outer join query in 10G

Question

Dear Mr./Mrs./Ms. Oracle expertise,
The following query structure can function properly in Oracle 9i, but not work in Oracle 10G.
Please kindly advise what happened in Oracle 10G?
Is it a bug in 10G? If yes, any patch for it?
select a.col1,
a.col2,
a.col5,
b.col3,
b.col4
from t1 a
inner join t2 c on c.col1 = a.col1
left join (select col3
col4
from t3) b
on b.col1 = a.col1
and a.col2 = 'Y' <---------- seems 10G cannot allow this condition
where a.col5 = 123;
Purpose of above SQL
====================
Only those records from t1 table with a.col2 = 'Y' will
do the left outer join to "b" table and get the columns b.col3 and b.col4
Result set in Oracle 9i
=======================
col1 col2 col5 col3 col4
AAA N 111
BBB N 222
CCC Y 333 XYZ OOO
DDD Y 444 QPR 111
Result set in Oracle 10G
========================
col1 col2 col5 col3 col4
AAA N 111
BBB N 222
CCC Y 333
DDD Y 444
Rgds,
Ken Chan

Answer 1

Dear Schneider,
Sorry that there was a typo in my query.
Below is the revised query.
select a.col1,
a.col2,
a.col5,
b.col3,
b.col4
from t1 a
inner join t2 c on c.col1 = a.col1
left join (select col1,
col3,
col4
from t3) b
on b.col1 = a.col1
and a.col2 = 'Y' <---------- seems 10G cannot allow this condition
where a.col5 = 123;
Thanks.
Rgds,
ken Chan