CREATE TRIGGER bu_projects_tomerge_0
BEFORE UPDATE OF
    resolve
ON
    projects_tomerge
FOR EACH ROW WHEN
    NEW.resolve = 1 AND
    OLD.hub_id != 0
BEGIN

    SELECT debug(
        'TRIGGER bu_projects_tomerge_0',
        OLD.project_id
    );

    UPDATE
        projects
    SET
        hub_id = (
            SELECT
                t.id
            FROM
                topics t
            WHERE
                t.uuid = (
                    SELECT
                        project_updates.hub_uuid
                    FROM
                        project_updates
                    INNER JOIN
                        updates
                    ON
                        updates.id = project_updates.update_id
                    WHERE
                        project_updates.project_id = OLD.project_id AND
                        project_updates.hub_uuid IS NOT NULL
                    ORDER BY
                        updates.mtime DESC,
                        updates.uuid
                    LIMIT
                        1
                )
            )
    WHERE
        id = OLD.project_id
    ;

END;