How to remove duplicate entries from a mysql db?

Posted by Yegor on Stack Overflow See other posts from Stack Overflow or by Yegor
Published on 2010-05-19T16:35:17Z Indexed on 2010/05/19 16:40 UTC
Read the original article Hit count: 111

Filed under:

mysql

|

remove-duplicates

I have a table with some ids + titles. I want to make the title column unique, but it has over 600k records already, some of which are duplicates (sometimes several dozen times over).

How do I remove all duplicates, except one, so I can add a UNIQUE key to the title column after?

© Stack Overflow or respective owner

Related posts about mysql

How to remove MySQL completely with config and library files on ubuntu 12.04 gnome 3.0

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I tried everything till now: sudo apt-get remove mysql-server mysql-client mysql-common sudo apt-get purge mysql-server mysql-client mysql-common sudo apt-get autoremove and even more commands... But whenever I am trying to locate mysql. I get a no. of files related to mysql command: shell>>… >>> More
mysql: Cannot load from mysql.proc. The table is probably corrupted

as seen on Server Fault - Search for 'Server Fault'
Mysql was started: /usr/bin/mysqld_safe --datadir=/srv/mysql/myDB --log-error=/srv/mysql/logs/mysqld-myDB.log --pid-file=/srv/mysql/pids/mysqld-myDB.pid --user=mysql --socket=/srv/mysql/sockets/mysql-myDB.sock --port=3700 but when I'm trying to do something: ERROR 1548 (HY000) at line 1: Cannot… >>> More
Why is there a /etc/init.d/mysql file on this Slackware machine? How could it have gotten there?

as seen on Server Fault - Search for 'Server Fault'
A client of my IT-consulting service owns a web-development shop. He's been having problems with a Slackware 12.0 server running MySQL 5.0.67. The machine was set up by the client's sysadmin, who left on bad terms. My client no longer employs a sysadmin. As far as I can tell, the only copy of MySQL… >>> More
mysql: Bind on unix socket: Permission denied

as seen on Server Fault - Search for 'Server Fault'
Can't start mysql with: sudo /usr/bin/mysqld_safe --datadir=/srv/mysql/myDB --log-error=/srv/mysql/logs/mysqld-myDB.log --pid-file=/srv/mysql/pids/mysqld-myDB.pid --user=mysql --socket=/srv/mysql/sockets/mysql-myDB.sock --port=3700 120222 13:40:48 mysqld_safe Starting mysqld daemon with databases… >>> More
MySQL – Learning MySQL Online in 6 Hours – MySQL Fundamentals in 320 Minutes

as seen on SQL Authority - Search for 'SQL Authority'
MySQL is one of the most popular database language and I have been recently working with it a lot. Data have no barrier and every database have their own place. I have been working with MySQL for quite a while and just like SQL Server, I often find lots of people asking me if I have a tutorial which… >>> More

Related posts about remove-duplicates

remove duplicates from contextual menu snow leopard

as seen on Super User - Search for 'Super User'
i have a few cases in which i get the name of the same app twice in the contextual menu...how can i clean the contextual menu to not display duplicate nam >>> More
Remove duplicates from a sorted ArrayList while keeping some elements from the duplicates

as seen on Stack Overflow - Search for 'Stack Overflow'
Okay at first I thought this would be pretty straightforward. But I can't think of an efficient way to solve this. I figured a brute force way to solve this but that's not very elegant. I have an ArrayList. Contacts is a VO class that has multiple members - name, regions, id. There are duplicates… >>> More
Remove Duplicates from LEFT OUTER JOIN

as seen on Stack Overflow - Search for 'Stack Overflow'
Hey folk my question is quite similar to http://stackoverflow.com/questions/757957/restricting-a-left-join I have a variation in that request though and the comment didn't allow too many characters hence posting as a new question. I hope this doesn't go against the posting rules/etiquette. Assuming… >>> More
Remove duplicates in NSdictionary

as seen on Stack Overflow - Search for 'Stack Overflow'
Is there a way to remove duplicate (key-value) pairs from NSDictionary ? EDIT: My description was misleading, I have duplicate pairs e.g. key1-value1 key1-value1 key2-value2 key1-value1 etc.. >>> More
Remove Duplicates from List of HashMap Entries

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a List<HashMap<String,Object>> which represents a database where each list record is a database row. I have 10 columns in my database. There are several rows where the values of 2 particular columns are equals. I need to remove the duplicates from the list after the list is updated… >>> More