mysql - 列同时不能等于某个值(mysql)

Question

我有这张表:

+------+----------+-------------+
| id   | category | category_id |
+------+----------+-------------+
|  1   | 2        | 12          |
|  2   | 1        | 12          |
|  3   | 3        | 54          |
|  4   | 3        | 17          |
|  5   | 2        | 14          |
+------+----------+-------------+

我需要获得以下内容:
当类别 = 2 时:category_id != 12
即

+------+----------+-------------+
| id   | category | category_id |
+------+----------+-------------+
|  2   | 1        | 12          |
|  3   | 3        | 54          |
|  4   | 3        | 17          |
|  5   | 2        | 14          |
+------+----------+-------------+

此代码不起作用:

SELECT * FROM `table` WHERE `category`!=2 AND `category_id`!=12

Answer 1

我想你想要OR:

select *
from `table`
where `category` != 2
    or `category_id` != 12

根据De Morgan's law ，等同于:

select *
from `table`
where not (
        `category` = 2
        and `category_id` = 12
        )

内容为 - 获取除类别为 2 且category_id 为 12 的所有行(在一行中)