title: SqlAlchemy: case statement (case - if - then -else)
body: <p>I'm wondering if there's a way to create a <code>case</code> statement with SqlAlchemy, e.g. the <a href="http://www.postgresql.org/docs/current/static/functions-conditional.html">postgresql version</a> </p>
  
  <p>Maybe literal SQL is the way to go if there is no easy way of doing it?</p>