使用SubQuery MySQL插入 [英] INSERT INTO with SubQuery MySQL

问题描述

我有这句话:

INSERT INTO qa_costpriceslog (item_code, invoice_code, item_costprice)
    VALUES (1, 2, (SELECT item_costprice FROM qa_items WHERE item_code = 1));

我正在尝试插入一个值，该值复制了item_costprice的相同数据，但显示了错误:

I'm trying to insert a value copy the same data of item_costprice, but show me the error:

Error Code: 1136. Column count doesn't match value count at row 1

我该如何解决?

推荐答案

在SELECT语句中使用带有别名的数字文字. SELECT组件周围不需要().

Use numeric literals with aliases inside a SELECT statement. No () are necessary around the SELECT component.

INSERT INTO qa_costpriceslog (item_code, invoice_code, item_costprice)
  SELECT
    /* Literal number values with column aliases */
    1 AS item_code,
    2 AS invoice_code,
    item_costprice
  FROM qa_items 
  WHERE item_code = 1;

请注意，在INSERT INTO...SELECT的上下文中，别名实际上并不是必需的，您可以只是SELECT 1, 2, item_costprice，但是在普通的SELECT中，您将需要别名来访问返回的列.

Note that in context of an INSERT INTO...SELECT, the aliases are not actually necessary and you can just SELECT 1, 2, item_costprice, but in a normal SELECT you'll need the aliases to access the columns returned.

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