MYSQL Duplicate Key Not Working

问题

Why is my ON DUPLICATE KEY UPDATE statement not working, I am after a way to not have duplicates in my table. With the below code I get duplicates

CMS::insertQuery("INSERT INTO {table} SET canid=?, categoryid=? ON DUPLICATE KEY UPDATE canid=?, categoryid=?", array($emailCheck['id'], $id, $emailCheck['id'], $id));

DB:

CREATE TABLE `table` (  `canid` int(10) NOT NULL,  `categoryid` int(10) NOT NULL,  UNIQUE KEY `canid` (`canid`,`categoryid`)) ENGINE=MyISAM DEFAULT CHARSET=latin1

Current Line I am trying to run:

CMS::insertQuery("INSERT INTO {table} SET canid=?, categoryid=? ON DUPLICATE KEY UPDATE canid=?, categoryid=? WHERE canid=?, categoryid=?", array($emailCheck['id'], $id, $emailCheck['id'], $id,$emailCheck['id'],$id));

回答1:

This is just a guess since you haven't provided your schema, but is one of the columns in your unique key nullable?

Edit:

As @G-Nugget says in the comments, you need a unique key on the columns in question:

If you specify ON DUPLICATE KEY UPDATE, and a row is inserted that would cause a duplicate value in a UNIQUE index or PRIMARY KEY, MySQL performs an UPDATE of the old row.

http://dev.mysql.com/doc/refman/5.6/en/insert-on-duplicate.html

You need to have a unique key on the combination of columns that should be unique.

eg:

ALTER TABLE yourTable ADD UNIQUE KEY (`canid`, `categoryid`);

Also, when asking database questions, please include SHOW CREATE TABLE for the tables in question.

回答2:

First thing to note, the field on which you would like to check for duplicate should be primary or unique. I was having the same issue and solved now.

http://dev.mysql.com/doc/refman/5.1/en/insert-on-duplicate.html

来源：https://stackoverflow.com/questions/12539757/mysql-duplicate-key-not-working

标签

php

mysql

duplicates