This can lead into additional space savings, if the table contains many NULL values.

如果表中包含很多null值，这样可以节省更多的空间。

youdao

In addition, if you have a table with many columns that aren't typically used, you are also wasting disk space with NULL value fields.

此外，如果您有不常用的含多个列的一个表，您也在通过null值字段浪费磁盘空间。

youdao

Enter a space if you want a value to be null.

如果您想要一个值为空，可以输入一个空格。

youdao