text: create function bv.q20_query()
      returns table (
          s_name    char(25),
          s_address varchar(40)
      )
      language plpgsql
  as
  $$
  begin
      return query select r.s_name, r.s_address
                   from bv.q20_result as r
                   group by r.s_suppkey, r.s_name, r.s_address;
  end
  $$;