After I moved back to Europe and Malta in order to set up our operations here, I was approached by a old friend of mine who wanted to know how to add a "UNIQUE" constraint and remove duplicates on a table, while keeping the newest records. He had been trying with "ALTER TABLE" but ran into problems as the older values were taken. So, to help him out, I first solved it based on his original idea, and then figured I would post a small note about the solution here.So, let's say we have the following structure . . .sql01 blogs> SHOW CREATE TABLE post1164\\G*************************** 1. row *************************** Table: post1164Create Table: CREATE TABLE `post1164` ( `a` int(10) unsigned NOT NULL AUTO_INCREMENT, `b` varchar(5) DEFAULT NULL, `c` varchar(5) DEFAULT NULL, PRIMARY KEY (`a`)) ENGINE=MyISAM AUTO_INCREMENT=7 DEFAULT CHARSET=latin11 row in set (0.00 sec). . . with a small amount of data in it:sql01 blogs> SELECT * FROM post1164;+---+------+------+| a | b | c |+---+------+------+| 1 | a | a1 | | 2 | a | a2 | | 3 | b | b1 | | 4 | c | c2 | | 5 | b | b2 | | 6 | c | c1 | +---+------+------+6 rows in set (0.00 sec)Now, if I were to use his original SQL, I would get a result similar to this: