title: MySQL calculating negative value on INT UNSIGNED
body: <p>I have a <code>start_date_time INT UNSIGNED</code> column in my table.</p>
  
  <p>I have a query like this</p>
  
  <pre><code>... WHERE (g.start_date_time-$currentTime) &gt; 0 ORDER BY (g.start_date_time-$currentTime)
  </code></pre>
  
  <p>And I get an error <code>Numeric value out of range: 1690 BIGINT UNSIGNED value is out of range in...</code>. If I set it to <strong>SIGNED</strong> of course everything works, but my question is is there a way to keep it <strong>UNSIGNED</strong> but anyway calculate negative values (I need just calculation, don't need to store them anywhere), or I should redefine my query?</p>