oracle query a database of all the tables and table space occupied

1. The look-up table in a user
SELECT SEGMENT_NAME, TABLESPACE_NAME, SUM (BYTES / 1024/1024) || 'M' from USER_EXTENTS WHERE segment_type = 'TABLE'
Group by SEGMENT_NAME, TABLESPACE_NAME

2.查所有的表
select SEGMENT_NAME,TABLESPACE_NAME,sum(BYTES/1024/1024)||'M' from dba_extents where SEGMENT_TYPE='TABLE'
group by SEGMENT_NAME,TABLESPACE_NAME