title: How can I query with a field parameter on a subrelation in Graphene-SQLAlchemy
body: <p>I am trying to figure out how I can accept a parameter and query on that field in a sub table in a GraphQL. </p>
  
  <p>This is an example.</p>
  
  <pre><code>query{
    allModels{
      edges{
        node{
          featureVectors(featureSize: 128){ #I want to query on this
            edges{
              node{
                modelSize
                featureVectors
              }
            }
          }
        }
      }
    }
  }
  </code></pre>
  
  <p>Here is that I'm using to query the data. It works to query the data, except that I would like to be able to pass a parameter to search for a specific for example, featureVectors(featureSize: 128). I can't seem to find anything in the Graphene-SQLAlchemy library to allow this natively. </p>
  
  <pre><code>class ModelModel(Base):
      __tablename__ = 'models'
  
      id = Column(Integer, primary_key=True, server_default=text("nextval('models_id_seq'::regclass)"))
      type = Column(Text)
      components = Column(Float)
      notes = Column(Text)
      feature_vectors = relationship("FeatureVector", back_populates='models')
  
  class FeatureVectorModel(Base):
  
      id = Column(BigInteger, primary_key=True, server_default=text("nextval('feature_vectors_id_seq'::regclass)"))
      model_size = Column(Integer)
      feature_vectors = Column(ARRAY(Float(precision=53)))
  
      models = relationship('Model', back_populates='feature_vectors')
  
  class Model(SQLAlchemyObjectType):
      class Meta:
          model = ModelModel
          interfaces = (relay.Node, )
  
  
  class ModelConn(relay.Connection):
      class Meta:
          node = Model
  
  
  class Query(graphene.ObjectType):
      node = relay.Node.Field(schema_cadlearn.Model)
      all_models = SQLAlchemyConnectionField(ModelConn)
  </code></pre>