Query: pubsub_subscriptions_for_pubsub_topic

with pubsub_subscription as (
  select
    self_link,
    topic_name
  from
    gcp_pubsub_subscription
  where
    project = split_part($1, '/', 6)
), pubsub_topic as (
  select
    self_link,
    name
  from
    gcp_pubsub_topic
  where
    project = split_part($1, '/', 6)
    and self_link = $1
)
select
  s.self_link as subscription_self_link
from
  pubsub_subscription s,
  pubsub_topic t
where
  s.topic_name = t.name;