SELECT tablespace_name,
       size_mb,
       free_mb,
       max_size_mb,
       max_free_mb,
       TRUNC((max_free_mb/max_size_mb) * 100) AS free_pct,
       RPAD(' '|| RPAD('X',ROUND((max_size_mb-max_free_mb)/max_size_mb*10,0), 'X'),11,'-') AS used_pct
FROM   (
        SELECT a.tablespace_name,
               b.size_mb,
               a.free_mb,
               b.max_size_mb,
               a.free_mb + (b.max_size_mb - b.size_mb) AS max_free_mb
        FROM   (SELECT tablespace_name,
                       TRUNC(SUM(bytes)/1024/1024) AS free_mb
                FROM   dba_free_space
                GROUP BY tablespace_name) a,
               (SELECT tablespace_name,
                       TRUNC(SUM(bytes)/1024/1024) AS size_mb,
                       TRUNC(SUM(GREATEST(bytes,maxbytes))/1024/1024) AS max_size_mb
                FROM   dba_data_files
                GROUP BY tablespace_name) b
        WHERE  a.tablespace_name = b.tablespace_name
       )
ORDER BY tablespace_name;