create function min(uuid, uuid)

    returns uuid

    immutable parallel safe

    language plpgsql as

$$

begin

    return least($1, $2);

end

$$;

​

create aggregate min(uuid) (

    sfunc = min,

    stype = uuid,

    combinefunc = min,

    parallel = safe,

    sortop = operator (<)

    );

​

create function max(uuid, uuid)

    returns uuid

    immutable parallel safe

    language plpgsql as

$$

begin

    return greatest($1, $2);

end

$$;

​

create aggregate max(uuid) (

    sfunc = max,

    stype = uuid,

    combinefunc = max,

    parallel = safe,

    sortop = operator (>)

    );