BigQuery supports querying and joining of data from external data sources on the Google Cloud Platform. The following are the data sources you can query from BigQuery:

• Google Cloud Storage files
• Google Bigtable database
• Google Drive files

The following demo shows how to query a CSV file in the Google Cloud Storage bucket using the BigQuery engine. The performance of the queries against external data sources is not as good as BigQuery data, and so it should be used with caution. The following are the steps to integrate Google Cloud Storage bucket files for querying:

1. Create a table definition file for the file in the Google Cloud Storage bucket
2. Link the data source as a table in the BigQuery dataset
3. Query the table in the BigQuery dataset