Datafiles and thier sizes

set pagesize 90 linesize 132
col tablespace_name format a30
col file_name format a55
col SizeInGB format 999,999
--col MaxGB format 999,999
-- col UserGB format 999,999

break on tablespace_name skip 1

compute sum of SizeInGB on tablespace_name
-- compute sum of MaxGB on tablespace_name
--compute sum of UserGB on tablespace_name

SELECT  tablespace_name,
        sum(bytes)/(1024*1024) SizeInGB ,
 --       sum(maxbytes)/(1024*1024) MaxGB,
--      sum(user_bytes)/(1024*1024) UserGB,
        file_name
  FROM  dba_data_files
 GROUP BY
        tablespace_name,
        file_name
 ORDER BY 1
/