mysql null values

[phpprog]

Hello All
What are the affects of making a column in a mysql table as NULL or NOT NULL.
What should be the default.

Any help is greatly appreciated..

Thanks
IM

[erick_w]

NULL means no data and is NOT "" (empty character). This link will help you to understand better: http://www.mysql.com/doc/en/Problems_with_NULL.html

[phpprog]

Thanks a lot