Php SQL查询构造
我最近创建了一个评分系统,用户按分数降序排列。首先,我习惯于将等级存储在自己的列中。我曾经运行此循环来更新排名:Php SQL查询构造,php,mysql,sql,Php,Mysql,Sql,我最近创建了一个评分系统,用户按分数降序排列。首先,我习惯于将等级存储在自己的列中。我曾经运行此循环来更新排名: $i = 1; $numberOfRows = mysql_query('SELECT COUNT(`id`) FROM sector0_players'); $scoreboardquery = mysql_query("SELECT * FROM sector0_players ORDER BY points DESC"); while(($row = m
$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++;
}
但是,这只是一个select语句。我是否可以绕过它并对其进行更改,使其像循环一样更新表?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;");
您可以尝试使用RANK函数。。我还没有实际执行SQL,但它应该可以工作
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
)
设置@rownum:=0;#MySQL返回一个空的结果集(即零行)。更新门派0_玩家设置记分板_排名=@rownum:=@rownum+1按点数顺序描述;#MySQL返回一个空的结果集(即零行)。如果您反复运行查询,它将显示该消息。尝试将记分牌排名更新为零,然后运行一次查询。这非常有效!你能解释一下为什么排名会因为这个问题而调整吗。我需要能够在将来修改它。:)有没有一种方法可以从PHP中执行此操作?您收到了这条消息,因为mysql只有在有任何更改时才会更新表。否则,它不会更新数据。假设某个特定记录的点数发生了变化,那么这个查询将更新x个数的行,而不是所有的行,除非单个记录的点数变化改变了整个排名顺序。
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
)