使用php更新mysql自定义排名字段

$servername = "localhost";
$username = "your_username";
$password = "your_password";
$dbname = "your_database";

// 使用mysqli连接数据库
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接是否成功
if ($conn->connect_error) {
    die("数据库连接失败: " . $conn->connect_error);
}

// 使用PDO连接数据库
try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch(PDOException $e) {
    die("数据库连接失败: " . $e->getMessage());
}

$sql = "SET @rank:=0;
        UPDATE users 
        SET rank = (@rank:=@rank+1) 
        ORDER BY score DESC";

// 使用mysqli执行SQL语句
if ($conn->query($sql) === TRUE) {
    echo "排名更新成功";
} else {
    echo "更新排名字段时出错: " . $conn->error;
}

// 使用PDO执行SQL语句
if ($conn->exec($sql) !== false) {
    echo "排名更新成功";
} else {
    echo "更新排名字段时出错";
}

// 使用mysqli关闭连接
$conn->close();

// 使用PDO关闭连接
$conn = null;