Home/ Questions/Q 71917
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-10T19:57:47+00:00

Is it possible to insert a row, but only if one of the values

  • 0

Is it possible to insert a row, but only if one of the values already in the table does not exist?

I’m creating a Tell A Friend with referral points for an ecommerce system, where I need to insert the friend’s email into the database table, but only if it doesn’t already exist in the table. This is because I don’t want any more than 1 person getting the referral points once the new customer signs up and purchases something. Therefore I want only one email ever once in the table.

I’m using PHP 4 and MySql 4.1.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. If the column is a primary key or a unique index:

    INSERT INTO table (email) VALUES (email_address) ON DUPLICATE KEY UPDATE email=email_address

    Knowing my luck there’s a better way of doing it though. AFAIK there’s no equivalent of ‘ON DUPLICATE KEY DO NOTHING’ in MySQL. I’m not sure about the email=email_Address bit, you could play about and see if it works without you having to specify an action. As someone states above though, if it has unique constraints on it nothing will happen anyway. And if you want all email addresses in a table to be unique there’s no reason to specify it as unique in your column definition.

    • 0