title: How to query an external csv file uploaded through StringIO in S3 in Snowflake with the right format?
body: <p>I've written these Python methods in my custom Airflow operator to convert a dictionary to a dataframe then to StringIO object and upload it to S3 as a CSV file without saving locally.</p>
  <pre><code>    def execute(self, context):
          s3_hook = S3Hook(aws_conn_id=self.s3_conn_id)
          retailer, d1 = context['task_instance'].xcom_pull(self.data_source)
          self._upload_file(d1, retailer, s3_hook)
  
      def _upload_to_s3(self, df, s3_hook):
          csv_buffer = StringIO()
          df.to_csv(csv_buffer)
          s3_hook.load_string(string_data=csv_buffer.getvalue(),
                              key=self.s3_key,
                              bucket_name=self.s3_bucket,
                              replace=True)
  
      def _upload_file(self, d, retailer, s3_hook):
          self.s3_key = f&quot;S3_STAGING/{retailer}/{retailer}_summary.csv&quot;
          df = pd.DataFrame.from_dict(d, orient=&quot;index&quot;)
          df.index.name = 'product_code'
          self._upload_to_s3(df, s3_hook)
  </code></pre>
  <p>The DAG runs and uploads the file successfully, <a href="https://i.stack.imgur.com/2inMZ.png" rel="nofollow noreferrer">and the file looks normal when using S3 query on it</a>. But when I try to query it in Snowflake:</p>
  <pre><code>select t.$1 as description,
         t.$2 as parent_company
  from @S3_STAGING/S3_STAGING/sample/sample_summary.csv as t
  </code></pre>
  <p><a href="https://i.stack.imgur.com/HDKYw.png" rel="nofollow noreferrer">All columns are concatenated into one for some reasons.</a> Is there any ways to fix this?</p>