title: How to ORDER BY a SUM() in MySQL?
body: <p>I have a table: "ID name c_counts f_counts "</p>
  
  <p>and I want to order all the record by <code>sum(c_counts+f_counts)</code>
  but this doesn't work:</p>
  
  <p><code>SELECT * FROM table ORDER BY sum(c_counts+f_counts) LIMIT 20;</code></p>