Does this query work on your DB?

Question

I'm on 9.2.0.4. The following query fails because it can't see the u.username column of the inner-inner query. But if I un-nest it by one level it works fine. It's as if the inline view hides the column names of the outermost query.
Is it supposed to work this way, or have I hit a bug?
If it works on your installation, could you please tell me your version number? Thanks.
SELECT u.username
     ,(SELECT object_name
       FROM (SELECT o.object_name
             FROM   all_objects o
             WHERE  o.owner = u.username
             ORDER BY o.object_id DESC)
       WHERE rownum = 1
      )  greatest_object_id
FROM   all_users u
ERROR at line 5:
ORA-00904: "U"."USERNAME": invalid identifier
SELECT u.username
     ,(SELECT count(*)
       FROM   all_objects o
       WHERE  o.owner = u.username) object_count
FROM   all_users u
USERNAME    OBJECT_COUNT
SYS                 2851
SYSTEM                31
HANSENE               15
...

Answer 1

I tested in 9.2.0.6 and didn't work either. I think it should work... can be a bug, not sure. An alternate way is:
select
u.username,
(select o.object_name from all_objects o where o.owner = u.username and o.object_id = (select max(m.object_id) from all_objects m where m.owner = o.owner)) greatest_object_id
from
all_users u;