Query: ec2_instances_for_ec2_gateway_load_balancer

select
  instance.arn as instance_arn
from
  aws_ec2_target_group tg,
  aws_ec2_instance instance,
  jsonb_array_elements(tg.target_health_descriptions) thd
where
  instance.instance_id = thd -> 'Target' ->> 'Id'
  and $1 in
  (
    select
      jsonb_array_elements_text(tg.load_balancer_arns)
  );