Counting rows in MySQL (highscore) - php

Question

I've created a game with a highscore table in MySQL.
I have a "My scores" button that needs to retrieve the users scores, e.g.:
10. John 395
42. John 340
90. John 10
How should I go out retrieving the rank (10th, 42th, 90th) of each score of the user?
I could pull all the scores from the database and iterate through them but that doesn't seem like a good solution.
Let me try to expand:
I retrieve all MY scores from the database. E.g. 10 scores. I want to display these 10 scores however I won't know what the rank of these scores is compared to the other scores in my database! (10th, 16th, etc) ..Hope that makes more sense...
Thanks

Answer 1

For the position in the total list you either need to build up a list every time you want this overview, or use a stored procedure to build a list for a given moment. You could 'cache' a list on a given interval. Or maybe update a list when some one played a game that would change the top 100.
As #WhiteElephant suggested, you'd be making the table every time you want the data.
#stefandoorn suggest to not use the optimized count of sql, i think this is not efficient enough for these kind of computations.

Answer 2

A simple SQL query would do it for you. For example, if you want the 10th score, you could use:
SELECT name, score FROM highscores ORDER BY score DESC LIMIT 1 OFFSET 9
The offset will always be the position required - 1.
If you want to have the associated rank as a column beside the score, you could do the following:
SELECT #rownum:=#rownum+1 position, name, score FROM (SELECT #rownum:=0) r, highscores ORDER BY score DESC
This doesn't work with an offset (the position number will always start at 1). The result would be something like the following:
+----------+-------------+-------+
| position | name | score |
+----------+-------------+-------+
| 1 | Player 1 | 27681 |
| 2 | Player 2 | 14982 |
+----------+-------------+-------+
But I think the best solution is to just loop through the returned values with an index and use the index to keep track of the position.

Answer 3

SELECT
id, name, score,(select count(*) FROM highscores AS higherscores WHERE higherscores.score>currentscores.score)+1 AS rank
FROM
highscores AS currentscores
WHERE name="john"
;

Answer 4

Just use ORDER BYscoreDESC in the end of your query to sort them in reversed order (from high to low). When iterating and showing it in PHP you can use a count:
Query e.g.: SELECT * FROM scores ORDER BY score DESC
$count = 1;
$sql = 'SELECT * FROM scores ORDER BY score DESC';
$result = mysql_query($sql) or die(mysql_error());
while($fetch = mysql_fetch_object($result)) {
echo $count . ' ' . $fetch->score . '<br />';
$count++;
}