Display free, used and total space per tablespace in a database

Query to get tablespace information from Oracle database - total, used and free space, extents
etc.

select a.tablespace_name, round(c.tbytes/1024/1024, 2) as TMB,
	   round(b.ubytes/1024/1024, 2) as UMB,
	   round((c.tbytes - b.ubytes)/1024/1024, 2) as FMB, 
	   a.initial_extent, a.next_extent, a.max_extents, a.status, a.extent_management
from
	(select tablespace_name, initial_extent, next_extent, max_extents, status, extent_management
	from dba_tablespaces) a,
	(select tablespace_name, sum(bytes) as ubytes
	from dba_segments
	group by tablespace_name) b,
	(select tablespace_name, sum(bytes) as tbytes
	from dba_data_files
	group by tablespace_name) c
where b.tablespace_name (+)= a.tablespace_name
and c.tablespace_name (+)= a.tablespace_name
order by fmb asc
/