Размер таблиц схемы Oracle

--Для SYSDBA

select t.TABLE_NAME, sum(s.bytes)/1048576 "SIZE (MB)"
from dba_segments s join dba_tables t on t.owner=s.owner and t.TABLE_NAME=s.SEGMENT_NAME
where t.owner=upper('<OWNER_NAME>')
group by t.TABLE_NAME
order by sum(s.bytes) desc;

--Для пользователя схемы:

select t.TABLE_NAME, sum(s.bytes)/1048576 "SIZE (MB)"
from user_segments s join user_tables t on t.TABLE_NAME=s.SEGMENT_NAME
group by t.TABLE_NAME
order by sum(s.bytes) desc;