title: mysql update another column to primary key value
body: <p>Is there a way to set the value of another column to primary key (auto increment)?</p>
  
  <p>Basically what I am trying to achieve is this</p>
  
  <pre><code>ID     Stuff
  ----   ------
  1      1
  2      324
  3      64
  4      94
  5      ...
  </code></pre>
  
  <p>Now when I am adding the the fifth row with a query like </p>
  
  <pre><code>INSERT into TABLE values(NULL, NULL);
  </code></pre>
  
  <p>So when the second value is <code>NULL</code> I want it to be equal to ID.</p>
  
  <p>I tried INSERT triggers but it doesnt work. Any ideas?</p>