title: SQLAlchemy - Combine Textual query with a filter
body: <p>I'm using <strong>SA 0.6.6</strong>, <strong>Python 2.66</strong> and <strong>Postgres 8.3</strong>. </p>
  
  <p>I have certain queries which require somewhat complex security check that can be handled with a <code>WITH RECURSIVE</code> query.  What I'm trying to do is combine a textual query with a query object so I can apply filters as necessary.</p>
  
  <p>My original thought was was to create my text query as a subquery and then combine that with the user's query and filters.  Unfortunately, this isn't working.</p>
  
  <pre><code>subquery = session.query(sharedFilterAlias).\
                     from_statement(sharedFilterQuery).subquery()
  </code></pre>
  
  <p>This results in this error: </p>
  
  <pre><code>AttributeError: 'Annotated_TextClause' object has no attribute 'alias'
  </code></pre>
  
  <p>Is there anyway to combine a textual query with SQLAlchemy's query object?</p>