title: Does COUNT(*) always return a result?
body: <p>If I run a query such as:</p>
  
  <pre><code>SELECT COUNT(*) as num FROM table WHERE x = 'y'
  </code></pre>
  
  <p>Will it always return a result, even when the query doesn't match any record? Or do I need to validate and make sure a row is returned as the result?</p>