Query: Download results to Arrow

Run a query and get Arrow table.

Code Sample

Python

Before trying this sample, follow the Python setup instructions in the BigQuery Quickstart Using Client Libraries. For more information, see the BigQuery Python API reference documentation.


from google.cloud import bigquery

# Construct a BigQuery client object.
client = bigquery.Client()

sql = """
WITH races AS (
SELECT "800M" AS race,
    [STRUCT("Rudisha" as name, [23.4, 26.3, 26.4, 26.1] as splits),
    STRUCT("Makhloufi" as name, [24.5, 25.4, 26.6, 26.1] as splits),
    STRUCT("Murphy" as name, [23.9, 26.0, 27.0, 26.0] as splits),
    STRUCT("Bosse" as name, [23.6, 26.2, 26.5, 27.1] as splits),
    STRUCT("Rotich" as name, [24.7, 25.6, 26.9, 26.4] as splits),
    STRUCT("Lewandowski" as name, [25.0, 25.7, 26.3, 27.2] as splits),
    STRUCT("Kipketer" as name, [23.2, 26.1, 27.3, 29.4] as splits),
    STRUCT("Berian" as name, [23.7, 26.1, 27.0, 29.3] as splits)]
    AS participants)
SELECT
race,
participant
FROM races r
CROSS JOIN UNNEST(r.participants) as participant;
"""
query_job = client.query(sql)
arrow_table = query_job.to_arrow()  # Make an API request.

print(
    "Downloaded {} rows, {} columns.".format(
        arrow_table.num_rows, arrow_table.num_columns
    )
)
print("\nSchema:\n{}".format(repr(arrow_table.schema)))