windmill/system_prompts/languages/bigquery.md

BigQuery

Arguments use @name syntax.

Name the parameters by adding comments before the statement:

-- @name1 (string)
-- @name2 (int64) = 0
SELECT * FROM users WHERE name = @name1 AND age > @name2;

Receiving an S3Object as a script parameter

Declare the arg with type (s3object). Windmill renders an S3 file picker for it, downloads the file, and binds it as a STRING JSON parameter — Parquet/CSV files are decoded server-side into a JSON array of records, JSON/JSONL pass through. Consume with JSON_EXTRACT_ARRAY / JSON_VALUE:

-- @file (s3object)
SELECT
  CAST(JSON_VALUE(row, '$.id') AS INT64) AS id,
  JSON_VALUE(row, '$.name') AS name
FROM UNNEST(JSON_EXTRACT_ARRAY(@file)) AS row;

Streaming query results to S3

Add a -- s3 directive at the top of the script to stream the result set to S3 instead of returning rows. Windmill writes the file and returns its S3Object as the script result.

-- s3 prefix=exports/users format=parquet
SELECT id, name FROM users;

All keys are optional: prefix (object key prefix), storage (named storage — omit to use the workspace default), format (json (default), parquet, or csv). Use this for large result sets — rows stream directly to S3 instead of being buffered, bypassing the 10000-row return cap.