我的 MySQL 语句有什么问题？

Question

UPDATE table1 SET announcer = ( SELECT memberid
FROM ( table1
JOIN users ON table2.username = table1.announcer
) AS a
WHERE a.username = table1.announcer )

#1064 - 您的 SQL 语法有错误；检查手册 对应你的MySQL服务器 正确使用语法的版本 靠近“某个地方” a.用户名=table1.播音员)' 在第 1 行

Answer 1

尝试：

UPDATE announcements a
SET announcer =
(SELECT memberid
FROM users u
WHERE u.username = a.announcer)

Answer 2

您还可以在更新中进行加入

UPDATE announcements JOIN users
SET announcements.announcer=users.memberid
WHERE announcements.username=users.username;

注意：出于安全原因（直到您确定的播音员被正确复制），我会创建一个新列，然后说anouncerNew

UPDATE announcements JOIN users
SET announcements.announcerNew=users.memberid
WHERE announcements.username=users.username;