Query: filestorage_filesystem_by_creation_month

with filesystems as (
  select
    title,
    time_created,
    to_char(time_created, 'YYYY-MM') as creation_month
  from
    oci_file_storage_file_system
  where
    lifecycle_state <> 'DELETED'
),
months as (
  select
    to_char(d, 'YYYY-MM') as month
  from
    generate_series(
      date_trunc(
        'month',
        (
          select
            min(time_created)
          from
            filesystems
        )
      ),
      date_trunc('month', current_date),
      interval '1 month'
    ) as d
),
filesystems_by_month as (
  select
    creation_month,
    count(*)
  from
    filesystems
  group by
    creation_month
)
select
  months.month,
  filesystems_by_month.count
from
  months
  left join filesystems_by_month on months.month = filesystems_by_month.creation_month
order by
  months.month;