ORACLE data look-up table occupied storage space

Query "Account / library" storage space occupied by the data
select sum (bytes) / 1024/ 1024 as "size (M)" from dba_segments where owner = ' account name / Library name'

Single query table data storage space occupied by
SELECT SUM (bytes) / (1024 * 1024) AS "size (M)" from user_segments
WHERE segment_name = Upper ( 'table');

In the table space, the query storage space occupied by the largest tables
SELECT * FROM (SELECT SEGMENT_NAME, SUM (BYTES) / 1024/1024 MB FROM DBA_SEGMENTS WHERE TABLESPACE_NAME = upper ( ' table space name') GROUP BY SEGMENT_NAME ORDER BY 2 DESC) WHERE ROWNUM <10;

In the "Account / library", the query storage space occupied by the largest tables
SELECT * FROM (SELECT SEGMENT_NAME, SUM (BYTES) / 1024/1024 MB FROM DBA_SEGMENTS WHERE owner = upper ( ' account name / Library name') GROUP BY SEGMENT_NAME ORDER BY 2 DESC) WHERE ROWNUM <10 ;