Programs Knowledge

col TABLESPACE_NAME format a20
col Size(MB) format a10
col Avail(MB) format a10
col Used(MB) format a10
select
  a.TABLESPACE_NAME,
  to_char(a.BYTES/(1024*1024),'999,999') "Size(MB)",
  to_char(round((a.BYTES-b.BYTES)/(1024*1024),0),'999,999') "Used(MB)",
  to_char(b.BYTES/(1024*1024),'999,999') "Avail(MB)"
from
  (select TABLESPACE_NAME, sum(BYTES) "BYTES" from dba_data_files group by tablespace_name) a,
  (select TABLESPACE_NAME,sum(BYTES) "BYTES" from dba_free_space group by tablespace_name) b
where a.TABLESPACE_NAME=b.TABLESPACE_NAME;