executed in a wide variety of
    different ways, each of which will produce the same set of
    results.  If it is computationally feasible, the query optimizer
    will examine each of these possible execution plans, ultimately
    selecting the execution plan that is expected to run the fastest.
   </p><div class="note"><h3 class="title">Note</h3><p>
     In some situations, examining each possible way in which a query
     can be executed would take an excessive amount of time and memory.
     In partic