CREATE OR REPLACE VIEW public.local_community_external_subscribers AS
 SELECT community.name AS "community.name",
    community.actor_id AS "community.actor_id",
    person.name AS "person.name",
    person.display_name AS "person.display_name",
    person.actor_id AS "person.actor_id",
    person.last_refreshed_at AS "person.last_refreshed_at",
    person.bot_account AS "person.bot_account"
   FROM ((community
     JOIN community_follower ON ((community_follower.community_id = community.id)))
     JOIN person ON ((community_follower.person_id = person.id)))
  WHERE (community.instance_id = 1);

This will create a view within the Lemmy database, for reusability. If you just want to run a one-off query or prefer to store it in other form, omit the first line.