Oracle Tablespace Boş Alan Miktarı

select a.TABLESPACE_NAME,
a.BYTES bytes_used,
b.BYTES bytes_free,
b.largest,
round(((a.BYTES-b.BYTES)/a.BYTES)*100,2) percent_used
from 
(
select  TABLESPACE_NAME,
sum(BYTES) BYTES 
from  dba_data_files 
group  by TABLESPACE_NAME
)
a,
(
select  TABLESPACE_NAME,
sum(BYTES) BYTES ,
max(BYTES) largest 
from  dba_free_space 
group  by TABLESPACE_NAME
)
b
where  a.TABLESPACE_NAME=b.TABLESPACE_NAME
order  by ((a.BYTES-b.BYTES)/a.BYTES) desc