Ranking by Group in MySQL

Question

I have a table with one column as follows:

name
-------
Michael
Michael
Michael
Michael
John
John
John
Alex
Alex

I need to rank them to give:

name    | rank
--------|------
Michael |1
Michael |2
Michael |3
Michael |4
John    |1
John    |2
John    |3
Alex    |1
Alex    |2

How can I perform that?

Answer 1

There's nothing in mysql that lets you do this directly, but you can hack it in:

SET @prev := null;

SET @cnt := 1;

SELECT name, IF(@prev <> name, @cnt := 1, @cnt := @cnt + 1) AS rank, @prev := name
FROM yourtable
ORDER BY name

This sort of thing is easier done in your client app, using the same basic logic.

Answer 2

Simple,

CREATE TABLE customer (
name CHAR(30) NOT NULL,
rank MEDIUMINT NOT NULL AUTO_INCREMENT,
PRIMARY KEY (name,rank)) ENGINE=MyISAM;

INSERT INTO customer (name) VALUES
('Michael'),('Michael'),('John'),('Alex'),('Michael'),('John');

SELECT * FROM customer ORDER BY name,rank;