Query: emr_cluster_by_age

with clusters as (
  select
    title,
    (status -> 'Timeline' ->> 'CreationDateTime') :: timestamp as created_at,
    to_char(
      (status -> 'Timeline' ->> 'CreationDateTime') :: timestamp,
      'YYYY-MM'
    ) as creation_month
  from
    aws_emr_cluster
),
months as (
  select
    to_char(d, 'YYYY-MM') as month
  from
    generate_series(
      date_trunc(
        'month',
        (
          select
            min(created_at)
          from
            clusters
        )
      ),
      date_trunc('month', current_date),
      interval '1 month'
    ) as d
),
clusters_by_month as (
  select
    creation_month,
    count(*)
  from
    clusters
  group by
    creation_month
)
select
  months.month,
  clusters_by_month.count
from
  months
  left join clusters_by_month on months.month = clusters_by_month.creation_month
order by
  months.month;