INSERT ...在mysql中的SELECT查询

Question

我有两张桌子：

`user1`
- full_name
- headline # this is empty

`user2`
- full_name
- headline # this has content

我想将headline从user2表插入到user1表中。这就是我到目前为止所做的：

insert into user1 set headline = (select headline from user2 where headline=headline)

但是，我收到一条错误消息，说select会返回多行。我如何正确发出此插入语句？

Answer 1

目前还不完全清楚你想做什么。特别是，当每个表中有多个记录时会发生什么？如果您要将标题从user2复制到user1匹配的full_name，则可以使用多表UPDATE语法来连接表并更新{{1 }}：

user1

Answer 2

如果你真的想要INSERT那么你想要

INSERT INTO user1 SELECT full_name, headline

如果你真的想要更新，那么你想要

UPDATE user1 SET headline = (SELECT headline FROM user2 WHERE user1.full_name = user2.full_name)