Tablespace Size

SQL> select tablespace_name, 'Mb'||' '||round(sum(bytes/1024/1024)) "Used_Size"

2 from dba_data_files
3 group by tablespace_name;

TABLESPACE_NAME Used_Size
------------------------------ -------------------------------------------
DENI Mb 3
EXAMPLE Mb 150
SYSAUX Mb 310
SYSTEM Mb 450
UNDOTBS1 Mb 875
USERS1 Mb 3629

6 rows selected.

SQL> select tablespace_name, 'Mb'||' '||round(sum(bytes/1024/1024)) "Free_Size"

2 from dba_free_space
3 group by tablespace_name;

TABLESPACE_NAME Free_Size
------------------------------ -------------------------------------------
DENI Mb 3
EXAMPLE Mb 70
SYSAUX Mb 19
SYSTEM Mb 4
UNDOTBS1 Mb 867
USERS1 Mb 1

6 rows selected.