mysql - 如何在 mysql 服务器上将 null 定义为整数值？

Question

我需要允许在 mysql 服务器上将 null 保存为整数值，我该怎么做？

Answer 1

假设您的问题是关于“不正确的整数值”错误消息...

mysql> CREATE TABLE `foo` (
    ->  `foo_id` INT(10) NOT NULL AUTO_INCREMENT,
    ->  `foo_size` INT(10) NOT NULL DEFAULT '0',
    ->  PRIMARY KEY (`foo_id`)
    -> ) ENGINE=MyISAM;
Query OK, 0 rows affected (0.05 sec)

mysql> INSERT INTO foo (foo_size) VALUES ('');
ERROR 1366 (HY000): Incorrect integer value: '' for column 'foo_size' at row 1

...这意味着您的服务器正在严格模式下运行(这实际上很好)。您可以禁用它:

mysql> SET @@session.sql_mode='';
Query OK, 0 rows affected (0.00 sec)

mysql> INSERT INTO foo (foo_size) VALUES ('');
Query OK, 1 row affected, 1 warning (0.00 sec)

mysql> SHOW WARNINGS;
+---------+------+------------------------------------------------------------+
| Level   | Code | Message                                                    |
+---------+------+------------------------------------------------------------+
| Warning | 1366 | Incorrect integer value: '' for column 'foo_size' at row 1 |
+---------+------+------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> SELECT * FROM foo;
+--------+----------+
| foo_id | foo_size |
+--------+----------+
|      1 |        0 |
+--------+----------+
1 row in set (0.00 sec)

...您的错误将降级为警告。