CREATE TRIGGER bu_hub_locations_tomerge_4
BEFORE UPDATE OF
    resolve
ON
    hub_locations_tomerge
FOR EACH ROW WHEN
    NEW.resolve = 1
BEGIN

    SELECT debug(
        'TRIGGER bu_hub_locations_tomerge_4',
        OLD.hub_location_id
    );

    UPDATE
        topics
    SET
        mtime = (
            SELECT
                updates.mtime
            FROM
                hub_location_updates
            INNER JOIN
                updates
            ON
                updates.id = hub_location_updates.update_id
            WHERE
                hub_location_updates.hub_location_id =
                    OLD.hub_location_id
            ORDER BY
                updates.mtime DESC,
                updates.uuid
            LIMIT
                1
        )
    WHERE
        id = OLD.hub_location_id
    ;

    DELETE FROM
        hub_locations_tomerge
    WHERE
        hub_location_id = OLD.hub_location_id
    ;

    SELECT RAISE(IGNORE);

END;