title: Complex multi-column mysql order by
body: <p>I have a Product Database with products ordered by popularity (number_sold).  The problem is that many of the popular products are out of stock.  I want to sort by number_sold where in_stock is at least 1, then display the out-of-stock products afterwards (still sorted by number_sold).</p>
  
  <p><strong>Example Data:</strong></p>
  
  <pre><code>Blue Car - stock 0 - sold 8
  Red Car - stock 2 - sold 4
  Yellow Car - stock 0 - sold 5
  Tan Car - stock 8 - sold 1
  Purple Car - stock 1 - sold 2
  </code></pre>
  
  <p>I want displayed in the following order:</p>
  
  <pre><code>1) Red
  2) Purple
  3) Tan
  4) Blue
  5) Yellow
  </code></pre>
  
  <p>Is this possible within one MySQL query?</p>