How To PHP - PHP Technology, PHP Tutorial, Database Tutorials, CMS System » Mysql Interview http://www.phpmind.com/blog Future of web development Tue, 25 Oct 2011 21:38:58 +0000 en hourly 1 http://wordpress.org/?v=3.2.1 How to remove duplicate entries from a table ? http://www.phpmind.com/blog/2010/04/how-to-remove-duplicate-entries-from-a-table/ http://www.phpmind.com/blog/2010/04/how-to-remove-duplicate-entries-from-a-table/#comments Wed, 21 Apr 2010 21:57:12 +0000 om http://www.phpmind.com/blog/?p=570 Removing Duplicate entries from Mysql database table are really simple. I have found some times interviewer ask tricky questions like this. PHP-MYSQL Beginners  just be careful !

It can all be done with three manual SQL steps! No PHP Coding required, and it works with MySQL 4 and above versions.

Step One -

View Code SQL
CREATE TABLE MyNewTable as
SELECT * FROM MyOldTable WHERE 1 GROUP BY [column to remove duplicates by];

Step Two – You hate to keep old table with all the duplicate entries, so drop it!

View Code SQL
DROP TABLE MyOldTable;
View Code SQL
RENAME TABLE MyNewTable TO MyOldTable;

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