title: Count days in date range?
body: <p>I have a query like this:</p>
  
  <pre><code>SELECT COUNT(*) AS amount
  FROM daily_individual_tracking
  WHERE sales = 'YES'
  AND daily_individual_tracking_date BETWEEN '2010-01-01' AND '2010-03-31'
  </code></pre>
  
  <p>I am selected from a date range. Is there a way to also get the total days in the date range?</p>