tti "Space Usage for Database"
set pagesize 55

col total_mb format 9,999,999.99
col used_mb format 9,999,999.99
col free_mb format 9,999,999.99
col free_% format 999.9

SELECT substr(total.name,1,25) tablspace_name,
       total_mb, 
       (total_mb-free_mb) used_mb, 
       free_mb,
       (free_mb/total_mb)*100 "FREE_%"
FROM
  (select tablespace_name, sum(bytes/1048576) free_mb
     from sys.dba_free_space
    group by tablespace_name
  ) Free,
  (select b.name,  sum(bytes/1048576) total_mb
     from sys.v_$datafile a, sys.v_$tablespace b
    where a.ts# = b.ts#
    group by b.name
  ) Total
WHERE free.tablespace_name = total.name
/

tti off