I'm using an INSERT ON DUPLICATE KEY statement for my website. It's for creating news items, so I figured I could use the same MySQL command for both creating and updating news items. However, when I use the following: INSERT INTO table (id,title,content) VALUES(NULL,"Test","Test"); Instead of creating a new auto increment value it throws an error. However, the command works on my main development server. But not on my laptop. Both versions of MySQL are the same, the only difference being MySQL was installed manually on my server, and with WAMP on my laptop. Are there any MySQL Variables that could be causing this?