Google BigQuery：创建表时将日期添加到表名

Question

I am writing a query I am planning to schedule using Big Query UI.

I would like to add a _TABLE_SUFFIX to this table which is equal to CURRENT_DATE.

How could I achieve that?

This is the query I am working on:

IF 
  today != DATE_SUB(DATE_TRUNC(CURRENT_DATE(), MONTH), INTERVAL 1 DAY)
THEN 
  CREATE TABLE `project.dataset.tablename_<insert_current_date_here>`
  AS
  SELECT CURRENT_DATE() as today;
END IF;

Answer 1

The best bet would be to generate the query dynamically, and then execute it statically.

This could be done using something like python.

from datetime import datetime

def get_query():
    return '''IF 
    today != DATE_SUB(DATE_TRUNC(CURRENT_DATE(), MONTH), INTERVAL 1 DAY)
    THEN 
    CREATE TABLE `project.dataset.%s`
    AS
    SELECT CURRENT_DATE() as today;
    END IF;''' % str(datetime.now())

Answer 2

BigQuery supports a template system for destination table names in scheduled queries. To add the current date to the table name, use the provided template syntax. For example, tablename_{run_time|"%Y%m%d"} would output tablename_YYYYMMDD .

Answer 3

You could (whether you should is another debate) create dynamic table names via BQ's SQL procedural language capability, specifically the EXECUTE IMMEDIATE statement.

eg

DECLARE today STRING DEFAULT STRING(DATE_SUB(DATE_TRUNC(CURRENT_DATE(), MONTH), INTERVAL 1 DAY));

EXECUTE IMMEDIATE format("""
CREATE TABLE `project.dataset.tablename_%s` AS
SELECT CURRENT_DATE() as today
""", today);

For more also see towardsdatascience.com/how-to-use-dynamic-sql-in-bigquery .

Note you might also now get error location issues with EXECUTE IMMEDIATE , if so try changing/checking your Processing location in Query Settings , see here