title: How to use NOT IN clause in sqlalchemy ORM query
body: <p>how do i convert the following mysql query to sqlalchemy?</p>
  
  <pre><code>SELECT * FROM `table_a` ta, `table_b` tb where 1
  AND ta.id = tb.id
  AND ta.id not in (select id from `table_c`)
  </code></pre>
  
  <p>so far i have this for sqlalchemy:</p>
  
  <pre><code>query = session.query(table_a, table_b)
  query = query.filter(table_a.id == table_b.id)
  </code></pre>