PATTERN: UNION similar things to combine them

untagged-ec2-instances-and-keypairs.sql

select title, id, resource from
  (
    select
      title,
      key_pair_id as id,
      'aws_ec2_key_pair' as resource,
      tags
    from
      aws_ec2_key_pair
    union
    select
      title,
      instance_id as id,
      'aws_ec2_instance' as resource,
      tags
    from
      aws_ec2_instance
  ) as untagged
where
  untagged.tags ->> 'owner' is null
  or untagged.tags ->> 'projectid' is null;