pan><span class="p">.</span><span class="n">field3</span>
<span class="k">FROM</span>   <span class="p">(</span><span class="k">SELECT</span> <span class="n">field1</span><span class="p">,</span>
               <span class="n">field2</span>
        <span class="k">FROM</span>   <span class="n">table1</span>
        <span class="k">WHERE</span>  <span class="n">field1</span> <span class="o">=</span> <span class="mi">1</span><span class="p">)</span> <span class="k">as</span> <span class="n">a</span>
    <span