Query: identity_groups_by_creation_month

with groups as (
  select
    title,
    time_created,
    to_char(time_created,
      'YYYY-MM') as creation_month
  from
    oci_identity_group
),
months as (
  select
    to_char(d,
      'YYYY-MM') as month
  from
    generate_series(date_trunc('month',
      (
        select
          min(time_created)
          from groups)),
      date_trunc('month',
        current_date),
      interval '1 month') as d
),
groups_by_month as (
  select
    creation_month,
    count(*)
  from
    groups
  group by
    creation_month
)
select
  months.month,
  groups_by_month.count
from
  months
  left join groups_by_month on months.month = groups_by_month.creation_month
order by
  months.month;