script for tablespace useage

Below is the script to get data about all the tablespaces in a database.

SELECT Total.name "Tablespace Name",
total_space "Total Size(MB)",
nvl(total_space-Free_space, 0) "Used Size(MB)",
nvl(Free_space, 0) "Free Size(MB)"
FROM
(select tablespace_name, sum(bytes/1024/1024) free_space
from sys.dba_free_space
group by tablespace_name
) Free,
(select b.name, sum(bytes/1024/1024) total_space
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
ORDER BY Total.name;