php - SQL 查询构造

Question

我最近创建了一个评分系统，其中用户按积分降序排列。首先，我曾经将排名存储在自己的列中。我曾经运行这个循环来更新排名:

$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++;
    }

这真的很困难，更不用说在大量用户上实际运行它的速度很慢。 相反，我尝试构建一个查询并最终得到这个结果。

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';

但是，这只是一条 select 语句。无论如何，我可以绕过它并更改它，以便它像循环一样更新表吗？

Answer 1

请尝试使用以下查询:

set @rownum:=0;
update sector0_players set scoreboard_rank=@rownum:=@rownum+1 ORDER BY points DESC;

PHP 代码可以是，

mysql_query("set @rownum:=0;");
mysql_query("update sector0_players set scoreboard_rank=@rownum:=@rownum+1 ORDER BY points DESC;");