如何将具有0000-00-00 00:00:00值的日期时间设置为NULL?

问题描述：

我需要在数据库上更改一些值.

I need to change a few values on my DB.

我忘记为表格设置可空值，并且默认情况下将其设置为0000-00-00 00:00:00.

I forgot to set nullable to the table and it set to 0000-00-00 00:00:00 by default.

现在我需要在NULL中转换该值.

Now I need to convert that value in NULL.

字段类型为Datetime.

The field type is Datetime.

我该怎么办?

我尝试使用典型的Update table set field = NULL WHERE field = '0000-00-00 00:00:00';，但是它不起作用.

I try with the typical Update table set field = NULL WHERE field = '0000-00-00 00:00:00'; but it doesn't work.

答

您需要首先使该列可为空:

You need to first make the column nullable:

ALTER TABLE mytable MODIFY COLUMN field DATETIME NULL;

然后更新值:

UPDATE mytable SET field = NULL WHERE field = '0000-00-00 00:00:00';