使用 PHP 开发知识问答网站中的用户积分排名和排行功能。

CREATE TABLE `users` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(50) NOT NULL,
  `email` varchar(50) NOT NULL,
  `password` varchar(255) NOT NULL,
  `created_at` timestamp NOT NULL DEFAULT current_timestamp(),
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE `scores` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `user_id` int(11) unsigned NOT NULL,
  `score` int(11) NOT NULL,
  `created_at` timestamp NOT NULL DEFAULT current_timestamp(),
  PRIMARY KEY (`id`),
  KEY `user_id` (`user_id`),
  CONSTRAINT `scores_user_id_foreign` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

function calculateScore($user_id, $score)
{
    // 将用户积分插入积分表
    $insertQuery = "INSERT INTO scores (user_id, score) VALUES ($user_id, $score)";
    // 执行插入操作...

    // 查询用户总积分
    $query = "SELECT SUM(score) as total_score FROM scores WHERE user_id = $user_id";
    // 执行查询操作...

    // 更新用户总积分和排名
    $updateQuery = "UPDATE users SET total_score = $total_score WHERE id = $user_id";
    // 执行更新操作...

    // 更新用户排名
    $updateRankQuery = "SET @rank := 0;";
    $updateRankQuery .= "
        UPDATE users SET rank = (@rank := @rank + 1) ORDER BY total_score DESC;
    ";
    // 执行更新操作...
}

function getRankings()
{
    $query = "SELECT name, total_score, rank FROM users ORDER BY rank";
    // 执行查询操作...
    // 输出排行列表...
}

// 用户获得积分后调用计算和更新积分函数
calculateScore($user_id, $score);

// 显示用户的排行
getRankings();