SELECT * FROM USER_TABLES;	-- Tables from connected schema
SELECT * FROM ALL_TABLES;	-- Tables available to connected schema	SELECT * FROM ALL_TABLES WHERE OWNER = 'SCHEMA_NAME';	SELECT * FROM ALL_TABLES WHERE TABLES_NAME = 'TABLE_NAME';
SELECT * FROM DBA_TABLES;	-- All Tables

SELECT * FROM ALL_TABLES;

SELECT DISTINCT TABLESPACE_NAME FROM DBA_EXTENTS ORDER BY TABLESPACE_NAME;
SELECT TABLESPACE_NAME, sum(BYTES / 1024 / 1024) AS MB
FROM DBA_DATA_FILES GROUP BY TABLESPACE_NAME;

-- NOTE: for Oracle ONLY
select *
from all_tables;

SELECT e.OWNER, e.SEGMENT_NAME, e.TABLESPACE_NAME, sum(e.bytes) / 1048576 AS Megs
FROM dba_extents e
WHERE e.OWNER = 'MY_USER' AND e.TABLESPACE_NAME = 'MY_TABLESPACE'
GROUP BY e.OWNER, e.SEGMENT_NAME, e.TABLESPACE_NAME
ORDER BY e.TABLESPACE_NAME, e.SEGMENT_NAME;