Question

Using PHP I’m inserting a record in a MySQL database. If the record is new I get the insert_id but if it already exists I can’t get the id using a single query.

Both of the following queries allow me to add the record or skip if it already exists:

INSERT INTO `emails` (`email`) VALUE ('[e-mail]') ON DUPLICATE KEY UPDATE `id`=`id`

INSERT IGNORE INTO `emails` (`email`) VALUE ('[e-mail]')

What is the right way to get the right result in both cases?

EDIT: Here’s my table syntax:

CREATE TABLE `emails` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `email` varchar(255) NOT NULL DEFAULT '',
  PRIMARY KEY (`id`),
  UNIQUE KEY `email` (`email`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

Answer 1

I suspect that it’s the value of LAST_INSERT_ID that ends up in insert_id.

Quote from the MySQL manual;

To make LAST_INSERT_ID() meaningful for updates, insert rows as follows:

INSERT INTO table (a,b,c) VALUES (1,2,3)
  ON DUPLICATE KEY UPDATE id=LAST_INSERT_ID(id), c=3;

Source: http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html