select a.TABLESPACE_NAME as "테이블스페이스",
round( sum(a.BYTES) ) || 'Byte' as "전체",
round( sum(b.FREES) ) || 'Byte' as "여유"
from ( select FILE_ID, TABLESPACE_NAME, SUM(BYTES) BYTES
from DBA_DATA_FILES -- 전체용량
group by FILE_ID, TABLESPACE_NAME) a,
( select TABLESPACE_NAME, FILE_ID, SUM(BYTES) FREES
from DBA_FREE_SPACE -- 여유용량
group by TABLESPACE_NAME, FILE_ID ) b
where a.TABLESPACE_NAME = b.TABLESPACE_NAME and a.FILE_ID = b.FILE_ID
group by a.TABLESPACE_NAME;