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Calculate a user's position in a leader board

Posted on 2008-06-18
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Last Modified: 2010-03-20
Hello

I have designed a league table which calculates points based on how many virtual cups of tea are given and received. 1 point for a given cup, 3 for a received.

A variable @I counts the position that the user ranks in the league, and it gives a Top 10.

How would I go about retrieving a given users position in the league, assuming most users will be outside the top ten? If a WHERE clause is used, the @I counter does not get to count the correct position in the league, and simply shows 1, as 1 record is returned.

Is a self-join needed...somehow?

Thanks!
+---------+---------------+-------------+---------------------+--------------+

| GIVE_ID | GIVE_UID_FROM | GIVE_UID_TO | GIVE_DATETIME       | GIVE_MESSAGE |

+---------+---------------+-------------+---------------------+--------------+

|       2 |     507426179 |   502129134 | 2008-05-02 17:16:44 | NULL         |

|       3 |     508580684 |   507426179 | 2008-05-02 17:21:31 | NULL         |

|       4 |     507426179 |   835984465 | 2008-05-02 17:23:39 | NULL         |

|       5 |     502129134 |   507426179 | 2008-05-02 17:23:45 | NULL         |

|       6 |     507426179 |   285100389 | 2008-05-02 17:23:46 | NULL         |

|       7 |     502129134 |   507426179 | 2008-05-02 17:24:56 | NULL         |

|       8 |     507426179 |   726170211 | 2008-05-02 17:29:14 | NULL         |

|       9 |     507426179 |   514816730 | 2008-05-02 17:29:54 | NULL         |

|      10 |     507426179 |   285100389 | 2008-05-02 17:47:33 | NULL         |

|      11 |     507426179 |   835984465 | 2008-05-02 18:00:00 | NULL         |

+---------+---------------+-------------+---------------------+--------------+
 
 

SET @I := 0;
 
 

		SELECT `GIVE_UID_FROM` , 

	

		( 	

			SELECT COUNT( * ) 

			FROM GIVE AS T 

			WHERE T.GIVE_UID_TO = SQ.GIVE_UID_FROM 

		)  	AS GIVE_TOTAL_RX,  	

	

		COUNT( `GIVE_ID` ) AS GIVE_TOTAL_TX,  	

	

		( 	

			SELECT (GIVE_TOTAL_RX *3) + COUNT( `GIVE_ID` ) 

		)  	AS GIVE_TOTAL_POINTS,

	

		@I := @I + 1 AS `GIVE_POSITION`
 

		FROM GIVE AS SQ

		GROUP BY `GIVE_UID_FROM`

		ORDER BY `GIVE_TOTAL_POINTS` DESC, `GIVE_TOTAL_RX` DESC

	LIMIT 10

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Question by:matthewhamer
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Accepted Solution

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matthewhamer earned 0 total points
ID: 21818609
I figured it out: Use a temporary table to store the results. Then query the temporary table.

Simply proceed the Select query with the following to generate an in-memory table which will be automatically destroyed when the connections drops. Perfect.
CREATE TEMPORARY TABLE LEAGUE ENGINE="MEMORY"

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