title: How to effectively use func.isnull in sql alchemy to get the two strings joined comma separated?
body: <p>Below is the code I have as part of a sqlalchemy query. Most of the time fist name is null. But Here in the case of below statement, always returns last name with a comma. Eg: <code>lastName</code>,
  How to add comma only if there's first name?</p>
  <pre><code>(func.isnull(
              prv.last_name,
              '') +
           ', ' +
           func.isnull(
              prv.first_name,
              '')).label('MyName')
  </code></pre>