select a.tablespace_name as tablespace_name ,a.total_mb,b.used_mb ,a.total_mb-b.used_mb as free_space from (select d.tablespace_name, sum(d.bytes/1024/1024) as total_mb from dba_data_files d group by d.tablespace_name) a, ( select s.tablespace_name,sum(s.bytes/1024/1024) as used_mb from dba_segments s group by tablespace_name) b where a.tablespace_name=b.tablespace_name order by tablespace_name select a.tablespace_name as tablespace_name ,a.total_mb,b.used_mb ,a.total_mb-b.used_mb as free ,free_space as free_space from (select tablespace_name, sum(bytes/1024/1024) as total_mb from dba_data_files group by tablespace_name) a, ( select tablespace_name,sum(bytes/1024/1024) as used_mb from dba_segments group by tablespace_name) b, (select tablespace_name,sum(bytes/1024/1024) as free_space from dba_free_space group by tablespace_name) c where a.tablespace_name=b.tablespace_name and b.tablespace_name=c.tablespace_name order by tablesp...