使用子查询 MySQL 插入 INTO

2022-01-09 00:00:00 subquery insert mysql

我有这个声明:

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

我正在尝试插入与 item_costprice 相同数据的值副本，但显示错误:

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

我该如何解决这个问题?

How i can solve this?

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，别名实际上不是必需的，您只需 SELECT 1, 2, item_costprice，但在正常的 SELECT 你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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