title: Is it possible to select and update an unknown value?
body: <p>I have the following table</p>
  
  <p>TABLE</p>
  
  <pre><code>ID      Person     Supervisor
  1       Michele    2
  2       James      4
  3       Jacob      4
  4       Francis    1
  </code></pre>
  
  <p>Let say Michele(1) leaves and I want her Supervisor(2) to take over supervising whoever Michele is supervising(Francis, 4)</p>
  
  <pre><code>SELECT id FROM TABLE WHERE supervisor = '1';
  </code></pre>
  
  <p>Would return me 2(Michele)</p>
  
  <p>To update I would simply do </p>
  
  <pre><code>UPDATE TABLE
  SET Supervisor = '2' &lt;-- can this not be hard-coded but "selected" in an UPDATE statement?
  WHERE Supervisor = '1';
  </code></pre>