Oracle: Query to find the 10 Largest Objects in DB

SELECT * FROM
(
select
    SEGMENT_NAME,
    SEGMENT_TYPE,
    BYTES/1024/1024/1024 GB,
    TABLESPACE_NAME
from
    dba_segments
order by 3 desc 
) WHERE
ROWNUM <= 10;


col owner format a15
col segment_name format a30
col segment_type format a15
col mb format 999,999,999
select owner
, segment_name
, segment_type
, mb
from (
select owner
, segment_name
, segment_type
, bytes / 1024 / 1024 "MB"
from dba_segments
order by bytes desc
)
where rownum < 11
/