lemmy/migrations/2023-07-18-082614_post_aggregates_community_id/up.sql

-- Your SQL goes here
ALTER TABLE post_aggregates
    ADD COLUMN community_id integer REFERENCES community ON UPDATE CASCADE ON DELETE CASCADE,
    ADD COLUMN creator_id integer REFERENCES person ON UPDATE CASCADE ON DELETE CASCADE;

CREATE OR REPLACE FUNCTION post_aggregates_post()
    RETURNS trigger
    LANGUAGE plpgsql
AS
$$
BEGIN
    IF (TG_OP = 'INSERT') THEN
        INSERT INTO post_aggregates (post_id,
                                     published,
                                     newest_comment_time,
                                     newest_comment_time_necro,
                                     community_id,
                                     creator_id)
        VALUES (NEW.id, NEW.published, NEW.published, NEW.published, NEW.community_id, NEW.creator_id);
    ELSIF (TG_OP = 'DELETE') THEN
        DELETE FROM post_aggregates WHERE post_id = OLD.id;
    END IF;
    RETURN NULL;
END
$$;

UPDATE post_aggregates
SET community_id=post.community_id,
    creator_id=post.creator_id
FROM post
WHERE post.id = post_aggregates.post_id;

ALTER TABLE post_aggregates
    ALTER COLUMN community_id SET NOT NULL,
    ALTER COLUMN creator_id SET NOT NULL;