tributes before the join starts. Then the two relations are
        scanned in parallel, and matching rows are combined to form
        join rows. This kind of join is
        attractive because each relation has to be scanned only once.
        The required sorting might be achieved either by an explicit sort
        step, or by scanning the relation in the proper order using an
        index on the join key.
       </p></li><li class="listitem"><p>
        <em class="firstterm">hash join</em>: the right r