Database_Size

Use following query to check your database size:

col "Database Size" format a20

col "Free space" format a20

col "Used space" format a20

select  round(sum(used.bytes) / 1024 / 1024 / 1024 ) || ' GB' "Database Size"

,   round(sum(used.bytes) / 1024 / 1024 / 1024 ) -

    round(free.p / 1024 / 1024 / 1024) || ' GB' "Used space"

,   round(free.p / 1024 / 1024 / 1024) || ' GB' "Free space"

from    (select bytes

    from    v$datafile

    union   all

    select  bytes

    from    v$tempfile

    union   all

    select  bytes

    from    v$log) used

,   (select sum(bytes) as p

    from dba_free_space) free

group by free.p

/