This SQL query sums the size in gigabytes of datafiles created each month from the last 9999 days and groups the results by month. It truncates the creation time to the month level, converts it to a string like "OCT 2022", and orders the results by month.

1. select to_char(Trunc(creation_time,'MM'), 'MON RRRR') "Month",
sum(bytes)/1024/1024/1024 "Growth in GB"
from sys.v_$datafile
where creation_time > SYSDATE-9999
group by Trunc(creation_time,'MM')
order by Trunc(creation_time,'MM');