How can I update multiple columns on multiple rows in postgresql using psycopg2

问题

I have a somewhat complex sql query that should update multiple columns on multiple rows in a table. Am trying to pass the multiple parameters to the query and also loop though the data to be updated through psycopg2 but I can't figure out a way to do this.

Here is the sample data I want to loop through.

 data = [(214, 'Feb', 545), (215, 'March', 466)]

So far here is the sql query I have

    query = """
      UPDATE table_1
      SET 
      date_from = 
       (CASE version 
           WHEN 1 THEN '1900-01-01' ELSE 
       ( SELECT date_to 
             FROM table_1 
             WHERE month = data.month
             AND cust_key = data.cust_key 
             AND prod_key = data.prod_key
         AND version = (
               SELECT version-1 
               FROM table_1 
               WHERE month = data.month 
               AND cust_key = data.cust_key 
               AND prod_key = data.prod_key
           ORDER BY version DESC LIMIT 1)
        ) 
    END), 
      date_to = current_date
      FROM (VALUES %s) AS data(cust_key, month, prod_key)
      WHERE month = data.month
      AND cust_key = data.cust_key 
      AND prod_key = data.prod_key
     """

Here is how I am passing my parameters

    WHERE month = data.month
    AND cust_key = data.cust_key 
    AND prod_key = data.prod_key

    FROM (VALUES %s) AS data(cust_key, month, prod_key)

And this is how I am executing the query

    cursor = db.cursor()
    execute_values(cursor, query, (data,))
    db.commit()
    return True

When I execute the query, I get this error psycopg2.errors.InvalidColumnReference: table "data" has 2 columns available but 3 columns specified I have gone through multiple solutions on this site but none seems to work for me.

Is there a way around this?

回答1:

Your data is already in the format as expected by psycopg2.extras.execute_values.

So, do not convert it to another tuple, simply do

execute_values(cursor, query, data)

来源：https://stackoverflow.com/questions/56749043/how-can-i-update-multiple-columns-on-multiple-rows-in-postgresql-using-psycopg2

标签

python

postgresql

psycopg2