title: Sqlalchemy how to filter column which contains both Null and integer values
body: <p>I have table with a nullable column which contains both types of values Null (as default) and integer:</p>
  
  <pre><code>class Node(db.Model):
      __tablename__ = "node"
      maintenance = db.Column(db.Integer, nullable=True)
  </code></pre>
  
  <p>The request is like this one:</p>
  
  <pre><code>maintenance = 1
  node_list = Node.query.filter(Node.maintenance != maintenance).all()
  </code></pre>
  
  <p>I need to select all cells which contains <code>Null</code> or <code>0</code> values.</p>
  
  <p>Thank you in advance!</p>