Mysql integer default value 0

Question

I have 4 integer columns in my table. They are not required to be filled. So some of them may be filled, some not. When they are not filled, mysql add 0 to that column. I tried to change column default value to NULL and it told Invalid default value. Is there any way to get empty row without having there the zero?

Answer 1

"Is there any way to get empty row without having there the zero?"

To have NULL in the column by default use the following syntax in create table:

`column` int(10) unsigned DEFAULT NULL,

To alter the existing column:

ALTER TABLE table_name CHANGE COLUMN `column_name` `column_name` int(10) unsigned DEFAULT NULL;