Query: ibm_is_volume_attachment_status

with attachment_state as (
  select
    case
      when jsonb_array_length(volume_attachments) > 0 then 'attached'
      else 'unattached'
    end as attachment_status
  from
    ibm_is_volume
)
select
  attachment_status,
  count(*)
from
  attachment_state
group by
  attachment_status;