In this article you’ll learn how to get user’s rank in mysql query. Check the link http://thinkdiff.net/mysql/how-to-get-rank-using-mysql-query

Some days ago I was working in a quiz project. Where user will play quiz and for each correct answer they will earn points. One of the task of this quiz application was, to get rank of a particular user. Now I am showing how could I solve this problem using mysql query.

Here is the table structure:

CREATE  TABLE IF NOT EXISTS `quiz_user` (
`uid` BIGINT UNSIGNED NOT NULL ,
`participated` SMALLINT UNSIGNED NULL DEFAULT 0 ,
`correct` SMALLINT UNSIGNED NULL DEFAULT 0 ,
`wrong` SMALLINT UNSIGNED NULL DEFAULT 0 ,
`created` DATETIME NULL ,
`updated` DATETIME NULL ,
PRIMARY KEY (`uid`) )
ENGINE = InnoDB

This table contains user records of quiz game. Here is an examples:

uid participated correct wrong  [Read more...]

I just read SQL: Ranking without self join, in which Shlomi Noach shares a nice MySQL-specific trick based on user-defined variables to compute rankings.

Shlomi's trick reminds me somewhat of the trick I came across little over a year ago to caclulate percentiles. At that time, several people pointed out to me too that using user-defined variables in this way can be unreliable.

The problem with user-defined variables

So what is the problem exaclty? Well, whenever a query assigns to a variable, and that same variable is

  [Read more...]