title: How to add TIMESTAMPDIFF to SqlSoup query?
body: <p>I have a reporting program running and using SqlSoup and have the entire query generated now by SqlSoup calls except for the MySqL Function <code>TIMESTAMPDIFF</code>.</p>
  
  <p>The actual SQL phrase should be</p>
  
  <pre><code>TIMESTAMPDIFF(PERIOD, start_time, end_time) &lt;= 60
  </code></pre>
  
  <p>I tried</p>
  
  <pre><code>from sqlalchemy.sql.expression import func
  </code></pre>
  
  <p>and a where-clause phrase (with <code>rc</code> a reference to the database and table)</p>
  
  <pre><code>where = and_(where, func.TIMESTAMPDIFF('PERIOD',rc.start_time,rc.end_time) &lt;= 60)
  </code></pre>
  
  <p>This compiles, but with logging on it shows the <code>PERIOD</code> as <code>%s</code> and then a parameter <code>PERIOD</code>
  below, which does not seem to work.</p>
  
  <p>Any ideas for doing this with SqlSoup?</p>