SET PAGESIZE 66 
COLUMN pct_used FORMAT 999.99 HEADING "% Used" 
COLUMN name FORMAT A16 HEADING "Tablespace Name" 
COLUMN mbytes FORMAT 99,999,999 HEADING "Total MBytes" 
COLUMN used FORMAT 99,999,999 HEADING "Used Mbytes" 
COLUMN free FORMAT 99,999,999 HEADING "Free Mbytes" 
 
BREAK ON REPORT
COMPUTE SUM OF mbytes ON REPORT 
COMPUTE SUM OF free ON REPORT 
COMPUTE SUM OF used ON REPORT 
 
SELECT
fs.tablespace_name name,
df.totalspace mbytes,
(df.totalspace - fs.freespace) used,
fs.freespace free,
100 * ((df.totalspace - fs.freespace)/ df.totalspace) pct_used 
FROM
(SELECT
tablespace_name,
ROUND(SUM(bytes) / 1048576) TotalSpace
FROM
dba_data_files
GROUP BY
tablespace_name
) df,
(SELECT
tablespace_name,
ROUND(SUM(bytes) / 1048576) FreeSpace
FROM
dba_free_space
GROUP BY
tablespace_name
) fs
WHERE
df.tablespace_name = fs.tablespace_name(+);