title: Order by not working in my SQL
body: <pre><code>order by no_of_products desc;
  </code></pre>
  
  <p>why the code above is working and the code below is not working. what should I do to make the below code work.</p>
  
  <pre><code>order by no_of_products sold desc; 
  </code></pre>
  
  <p>or </p>
  
  <pre><code>order by no_of_products sold' desc;
  </code></pre>