Query: ibm_is_vpc_by_size

with vpc_size as (
  select
    id,
    a -> 'cidr' as cidr_block,
    concat(
      '/',
      masklen((a ->> 'cidr') :: cidr),
      ' (',
      power(2, 32 - masklen((a ->> 'cidr') :: cidr)),
      ')'
    ) as size
  from
    ibm_is_vpc,
    jsonb_array_elements(address_prefixes) as a
)
select
  size,
  count(*)
from
  vpc_size
group by
  size;