title: SQL to SQLAlchemy translation
body: <p>I have a, somewhat odd, query that gets me all the items in a parent table that have no matches in its corresponding child table.</p>
  
  <p>If possible, id like to turn it into an SQLAlchemy query.  But I have no idea how.  I can do basic gets and filters, but this one is beyond my experience so far.  Any help you folks might give would be greatly appreciated.</p>
  
  <pre><code>class customerTranslations(Base):
      """parent table. holds customer names"""
      __tablename__ = 'customer_translation'
  
      id = Column(Integer, primary_key=True)
  
  class customerEmails(Base):
      """child table. hold emails for customers in translation table"""
      __tablename__ = 'customer_emails'
  
      id = Column(Integer, primary_key=True)
      parent_id = Column(Integer, ForeignKey('customer_translation.id'))
  </code></pre>
  
  <p>I want to build:</p>
  
  <pre><code>SELECT * FROM customer_translation 
  WHERE id NOT IN (SELECT parent_id FROM customer_emails)
  </code></pre>