----- Original Message ----- From: "Scott Haneda" > on 5/5/05 2:11 AM, Joerg Bruehe at [EMAIL PROTECTED] wrote: > Basically, I have a chopping cart, this one is a little weird, for reasons > not worth explaining, you have a cart when a user is not logged in, and they > *may* have one they made at some point when logged in. There is a chance > the logged in cart already has stuff in the non logged in cart, I don't want > duplicate items in the cart, so I want to just get rid of the oldest one.
I'd add a UNIQUE index on user id and product id (beware of the handling of NULL values!) and use REPLACE to add the new data. "REPLACE works exactly like INSERT, except that if an old record in the table has the same value as a new record for a PRIMARY KEY or a UNIQUE index, the old record is deleted before the new record is inserted." http://dev.mysql.com/doc/mysql/en/replace.html Regards, Jigal. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
