mysql - 1067 - Invalid default value

  时间:2019-02-11
本文章向大家介绍mysql - 1067 - Invalid default value,主要包括mysql - 1067 - Invalid default value使用实例、应用技巧、基本知识点总结和需要注意事项,具有一定的参考价值,需要的朋友可以参考一下。
                mysql 中无法设置默认值为函数或者表达式,如果你强制设置时,就会报错误:#1067 - Invalid default value。

这不是mysql的bug,而是故意这么设计的。参看:

http://dev.mysql.com/doc/refman/5.0/en/data-type-defaults.html

这里写道:

"The DEFAULT value  clause in a data type specification indicates a default value for a

column. With one exception, the default value must be a constant; it cannot be a function
or an expression. This means, for example, that you cannot set the default for a date
column to be the value of a function such as NOW()  or CURRENT_DATE."

简单来说就是默认值不能是函数和表达式,所有才有上面的错误信息。

下面是一个例子,不使用函数和表达式的默认值:

来自: http://stackoverflow.com/questions/168736/how-do-you-set-a-default-value-for-a-mysql-datetime-column

mysql> create table test (str varchar(32), ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP);

Query OK, 0 rows affected (0.00 sec)

mysql> desc test;

+-------+-------------+------+-----+-------------------+-------+

| Field | Type        | Null | Key | Default           | Extra |

+-------+-------------+------+-----+-------------------+-------+

| str   | varchar(32) | YES  |     | NULL              |       |

| ts    | timestamp   | NO   |     | CURRENT_TIMESTAMP |       |

+-------+-------------+------+-----+-------------------+-------+

2 rows in set (0.00 sec)


mysql> insert into test (str) values ("demo");

Query OK, 1 row affected (0.00 sec)

mysql> select * from test;

+------+---------------------+

| str  | ts                  |

+------+---------------------+

| demo | 2008-10-03 22:59:52 |

+------+---------------------+

1 row in set (0.00 sec)


mysql>



参考资料:


Date and Time Function
http://dev.mysql.com/doc/refman/5.0/en/date-and-time-functions.html



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