Query: vpc_by_size

with vpc_size as (
  select
    vpc_id,
    cidr_block,
    concat(
      '/', masklen(cidr_block),
      ' (', power(2, 32 - masklen(cidr_block :: cidr)), ')'
    ) as size
  from
    aws_vpc
)
select
  size,
  count(*)
from
  vpc_size
group by
  size;