Document the fast SQL method of creating all UDFs required by BigQuery Migration Service for SQL Translation

[danieldeleo]

-- SET YOUR DESIRED BQ REGION BELOW
SET @@location="us-east4";
/**********************************
 * DO NOT EDIT SQL BELOW THIS LINE
 **********************************/
DECLARE YOUR_PROJECT_ID STRING DEFAULT(@@project_id);
DECLARE YOUR_REGION STRING DEFAULT(@@location);
DECLARE region_suffix STRING DEFAULT(
  IF(YOUR_REGION="US", "", "_" || REPLACE(YOUR_REGION, "-", "_"))
);
-- Get regional UDFs
DECLARE cw_udf_ddls ARRAY<STRING>;
EXECUTE IMMEDIATE 
FORMAT("""
  SELECT ARRAY_AGG(ddl ORDER BY created) AS cw_udf_ddls
  FROM bqutil.fn%s.INFORMATION_SCHEMA.ROUTINES
  WHERE specific_name LIKE "cw_%%"
  """,
  region_suffix
)
INTO cw_udf_ddls;
-- Creates the fn dataset within your project
EXECUTE IMMEDIATE "CREATE SCHEMA IF NOT EXISTS " || YOUR_PROJECT_ID || ".fn" || region_suffix;
-- Creates all cw_* UDFs within your new fn dataset
FOR cw_udf_ddl IN (SELECT * FROM UNNEST(cw_udf_ddls) ddl)
DO EXECUTE IMMEDIATE REPLACE(REPLACE(cw_udf_ddl.ddl, "bqutil", YOUR_PROJECT_ID), "CREATE ", "CREATE OR REPLACE ");
END FOR;