read_table_bigquery.py

# Copyright 2019 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


def read_table():
    # [START bigquerystorage_pandas_tutorial_read_table]
    from google.cloud import bigquery

    bqclient = bigquery.Client()

    # Download a table.
    table = bigquery.TableReference.from_string(
        "bigquery-public-data.utility_us.country_code_iso"
    )
    rows = bqclient.list_rows(
        table,
        selected_fields=[
            bigquery.SchemaField("country_name", "STRING"),
            bigquery.SchemaField("fips_code", "STRING"),
        ],
    )
    dataframe = rows.to_dataframe(
        # Optionally, explicitly request to use the BigQuery Storage API. As of
        # google-cloud-bigquery version 1.26.0 and above, the BigQuery Storage
        # API is used by default.
        create_bqstorage_client=True,
    )
    print(dataframe.head())
    # [END bigquerystorage_pandas_tutorial_read_table]

    return dataframe