Query for database size

Question

I need a query which should display the current size of database and the size of the database one month back. I have tried with OEM but if the database goes down in between, it won't display the result.(OS-HP-Unix, Linux, Ver-8i,9i,10g)

Answer 1

user10929871 wrote:
My friend,
I have a query to find out the size one month back (Note: It doesn't include temp and redo logs size)
select sum(bytes)/1073741824 from v$datafile where
creation_time<to_date('01-03-2009','dd-mm-yyyy');That assumes that the only way you are adding space to the database is to add new data files which doesn't seem realistic. It's rather common to increase the size of the database by adding space to an existing data file or allowing a data file to autoextend at least to a point. Are you certain that, for the databases you're working with, the only way that anyone ever adds space to a database is to add new data files?
and for view the current size
select sum(bytes)/1073741824 from v$datafile ;
I have tested and it worked hope I am right if this queries are wrong plz let me know, now what I am looking for is a query where I don't need to provide the specific date just something like add_months function to this query and I want the above two queries into one, something like this but its giving me the wrong result
select sum(a.bytes)/1024/1024/1024, sum(b.bytes)/1024/1024/1024 from v$datafile a,v$datafile b where a.creation_time<to_date('01-03-2009','dd-mm-yyyy') and b.creation_time<=sysdate
/If you're sure that the "prior month" query is correct for your environment
SELECT a.gb old_size, b.gb new_size
  FROM (SELECT sum(bytes)/1073741824
          FROM v$datafile
         WHERE creation_time < trunc(sysdate,'MM')) a,
       (SELECT sum(bytes)/1073741824
          FROM v$datafile ) bJustin