SQL query construction - php

Question

I recently created a scoring system where the users are ordered by their points on descending basis. First I used to store ranks in a column of its own. I used to run this loop to update the rank:
$i = 1;
$numberOfRows = mysql_query('SELECT COUNT(`id`) FROM sector0_players');
$scoreboardquery = mysql_query("SELECT * FROM sector0_players ORDER BY points DESC");
while(($row = mysql_fetch_assoc($scoreboardquery)) || $i<=$numberOfRows){
$scoreid = $row['id'];
$mysql_qeury = mysql_query("UPDATE sector0_players SET scoreboard_rank = '$i' WHERE id = '$scoreid'");
$i++;
}
And it was really hard, not to mention slow to actually run this on a huge amount of users.
Instead, I tried to construct a query and ended up with this.
SET #rownum := 0;
SELECT scoreboard_rank, id, points
FROM (
SELECT #rownum := #rownum + 1 AS scoreboard_rank, id, points FROM sector0_players ORDER BY points DESC
)
as result WHERE id = '1';
But, this is just a select statement. Is there anyway I could get around it and change it so that it updates the table just as the loop does?

Answer 1

Please try using the following query :
set #rownum:=0;
update sector0_players set scoreboard_rank=#rownum:=#rownum+1 ORDER BY points DESC;
PHP code can be ,
mysql_query("set #rownum:=0;");
mysql_query("update sector0_players set scoreboard_rank=#rownum:=#rownum+1 ORDER BY points DESC;");

Answer 2

You can try using the RANK function .. I haven't actually executed the SQL, but it should work
UPDATE sector0_players
SET scoreboard_rank =
(
SELECT srank
FROM
(
SELECT id,points, RANK() OVER (ORDER BY points) AS srank
FROM sector0_players T
) D
WHERE D.id = sector0_players.id
AND D.points = sector0_players.points
)