如何使用 psycopg2 更新 postgresql 中多行的多列 [英] How can I update multiple columns on multiple rows in postgresql using psycopg2

问题描述

我有一个有点复杂的 sql 查询，它应该更新表中多行的多列.我正在尝试将多个参数传递给查询，并且还循环遍历要通过 psycopg2 更新的数据，但我想不出一种方法来做到这一点.

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.

这是我想要循环的示例数据.

Here is the sample data I want to loop through.

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

到目前为止，这是我的 sql 查询

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
     """

这是我传递参数的方式

    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)

这就是我执行查询的方式

And this is how I am executing the query

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

当我执行查询时，出现此错误 psycopg2.errors.InvalidColumnReference: table "data";有 2 列可用，但指定了 3 列我在这个网站上经历了多种解决方案，但似乎没有一个对我有用.

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.

有没有办法解决这个问题?

Is there a way around this?

推荐答案

您的 data 已经采用 psycopg2.extras.execute_values 预期的格式.

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

所以，不要把它转换成另一个元组，直接做

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

execute_values(cursor, query, data)

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