update record a set a.username = ( select b.name from user b where a.userid = b.id ) where a.username is null;
update record set username = user.name where record.id=user.id and username is null;
不会吧,sql语句不会有错,核对你的登陆用户名和表名。
update record a set a.username = ( select b.name from user b where a.userid = b.id ) where a.username is null; 这个语句应该是对的update record set username = user.name where record.id=user.id and username is null; 这个语句执行或许会成功,但结果是错的
( select b.name from user b where a.userid = b.id )
where a.username is null;
where record.id=user.id and username is null;
( select b.name from user b where a.userid = b.id )
where a.username is null;
这个语句应该是对的update record set username = user.name
where record.id=user.id and username is null;
这个语句执行或许会成功,但结果是错的