相关疑难解决方法(0)

我正在使用 H2 数据库并想要移动一些数据。为此，我创建了以下查询：

UPDATE CUSTOMER
SET EMAIL = SELECT service.EMAIL
FROM CUSTOMER_SERVICE AS service
INNER JOIN CUSTOMER AS customer ON service.ID = customer.CUSTOMER_SERVICE_ID;

当我现在在 H2​​ 控制台中执行它时，出现以下错误：

Scalar subquery contains more than one row; SQL statement:

UPDATE CUSTOMER
SET EMAIL = SELECT service.EMAIL
FROM CUSTOMER_SERVICE AS service
INNER JOIN CUSTOMER AS customer ON service.ID = customer.CUSTOMER_SERVICE_ID [90053-192] 90053/90053 (Hilfe)

这个错误告诉我什么？

编辑

我想通过查询实现什么：

其实每一个CUSTOMER都有一个CUSTOMER_SERVICE. 我只是想将其移至COLUMN EMAIL表格CUSTOMER_SERVICE中CUSTOMER。为此，我已经向用户添加了电子邮件列。我希望能够通过我的查询来做到这一点，但显然不能。