title: Fetch results from BigQueryOperator in airflow
body: <p>I am trying to fetch results from <code>BigQueryOperator</code> using airflow but I could not find a way to do it. I tried calling the <code>next()</code> method in the <code>bq_cursor</code> member (available in 1.10) however it returns <code>None</code>. This is how I tried to do it</p>
  
  <pre><code>import datetime
  import logging
  
  from airflow import models
  from airflow.contrib.operators import bigquery_operator
  from airflow.operators import python_operator
  
  
  yesterday = datetime.datetime.combine(
      datetime.datetime.today() - datetime.timedelta(1),
      datetime.datetime.min.time()
  )
  
  def MyChequer(**kwargs):
      big_query_count = bigquery_operator.BigQueryOperator(
          task_id='my_bq_query',
          sql='select count(*) from mydataset.mytable'
      )
  
      big_query_count.execute(context=kwargs)
  
      logging.info(big_query_count)
      logging.info(big_query_count.__dict__)
      logging.info(big_query_count.bq_cursor.next())
  
  default_dag_args = {
      'start_date': yesterday,
      'email_on_failure': False,
      'email_on_retry': False,
      'project_id': 'myproject'
  }
  
  with models.DAG(
          'bigquery_results_execution',
          # Continue to run DAG once per day
          schedule_interval=datetime.timedelta(days=1),
          default_args=default_dag_args) as dag:
  
      myoperator = python_operator.PythonOperator(
          task_id='threshold_operator',
          provide_context=True,
          python_callable=MyChequer
      )
  
      # Define DAG
      myoperator
  </code></pre>
  
  <p>Taking a look to <a href="https://github.com/apache/incubator-airflow/blob/v1-10-stable/airflow/contrib/hooks/bigquery_hook.py" rel="nofollow noreferrer">bigquery_hook.py</a> and <a href="https://github.com/apache/incubator-airflow/blob/v1-10-stable/airflow/contrib/operators/bigquery_operator.py" rel="nofollow noreferrer">bigquery_operator.py</a> it seems to be the only available way to fetch the results. </p>