mysql - 如何只用空格输入记录

I want to enter the record with white-space as a record in MySQL. I had tried to enter it through shell and phpmyadmin, the record enters but when I try to retrieve the record it returns as null. I had also set the column null = no even then returns nothing.

code is below through shell and php:

insert into first_replace(to_replace, with_replace) values(".", " ");

when creating mysql table row enable NULL or edit row and enable NULL