Space usage by lob column - oracle database script

SPACE USED BY LOB COLUMN:
SELECT s.bytes
FROM dba_segments s
JOIN dba_lobs l USING (OWNER,
                       segment_name)
WHERE l.table_name = '&table_name';

ACTUAL SPACE USED BY LOB:
SELECT nvl((sum(dbms_lob.getlength(&lob_column))),0) AS bytes
FROM &TABLE_NAME;