SELECT a.tablespace_name ,
       a.total "Total(Mb)" ,
       a.total - b.free "Used(Mb)" ,
       NVL( b.free , 0 ) "Free(Mb)" ,
       ROUND(( a.total - NVL( b.free , 0 ) ) *100/total , 0 ) "Used(%)"
FROM   (
        SELECT tablespace_name ,
               ROUND(( SUM( bytes ) /1024/1024 ) , 0 ) AS total
        FROM   dba_data_files
        GROUP  BY tablespace_name
       ) a ,
       (
        SELECT tablespace_name ,
               ROUND(( SUM( bytes ) /1024/1024 ) , 0 ) AS free
        FROM   dba_free_space
        GROUP  BY tablespace_name
       ) b
WHERE  a.tablespace_name = b.tablespace_name( + )
ORDER  BY a.tablespace_name ;