trouble with field NULL

I created a table with a field define as NULL, however when I insert values NULL , Mysql puts 0 instead of nothing , I don't understand why I have this trouble , Thanks - Before posting, please check: http://www.mysql

trouble with field NULL

I created a table with a field define as NULL, however when I insert values NULL , Mysql puts 0 instead of nothing , I don't understand why I have this trouble , Thanks - Before posting, please check: http://www.mysql.c