更新时间:2023-10-23 14:06:52
NULL
不等于任何东西.您需要明确接受空值:
NULL
doesn't compare equal to anything. You'll need to accept nulls explicitly:
where fk <> 4 or fk is null;
请参阅使用 NULL 了解更多信息关于 NULL
处理的信息.
See Working with NULL for more information about NULL
handling.