Parameter injection not working in BigQuery Vertex AI notebook for WEEK(WEEKDAY) - google-bigquery

Question

I'm using a Vertex AI notebook, running BigQuery IPython magics and injecting parameters.
params = {"day_of_week": "WEDNESDAY"}
%%bigquery sales_df --project $project_id --params $params
SELECT created_date, num_sales
FROM sales
WHERE DATE_DIFF(created_date, "2023-01-01", WEEK(#day_of_week)) BETWEEN -12 and 11
I'd expect this to work but it doesn't because WEEK expects a WEEKDAY argument (BQ docs). Hardcoding it as WEEK(WEDNESDAY) works but the parameter injection doesn't because it adds quotes around the string, effectively compiling it as WEEK("WEDNESDAY").
Is there any workaround here? I can't find a BQ method that turns a string weekday ("WEDNESDAY") into the day of week enum (WEDNESDAY).
UPDATE: I have raised this as a BigQuery feature request -https://issuetracker.google.com/issues/266201211.

Answer 1

You might try a dynamic SQL in your BigQuery magic.
params = {"day_of_week": "WEDNESDAY"}
%%bigquery sales_df --project $project_id --params $params
EXECUTE IMMEDIATE FORMAT("""
SELECT created_date, num_sales
FROM sales
WHERE DATE_DIFF(created_date, "2023-01-01", WEEK(%s)) BETWEEN -12 and 11
""", #day_of_week);
below is a working example I've tried.
%%bigquery --project your-project-id --params {"day_of_week": "WEDNESDAY"}
EXECUTE IMMEDIATE FORMAT("""
SELECT DATE_DIFF(CURRENT_DATE, "2023-01-01", WEEK(%s)) BETWEEN -12 and 11
""", #day_of_week)