title: MySQL - Best way to extract integer from string
body: <p>I am looking for the best way to extract the integer from these strings:</p>
  
  <pre><code>Next Day
  2 Days
  3 Days
  ...
  29 Days
  30 Days
  30+ Days
  </code></pre>
  
  <p>I could do this with substrings but I'm just wondering if there is a simpler function which would automatically attempt to convert the string to an integer (similar to PHP's <code>intval()</code> function, for example.</p>