使用 PHP 开发知识问答网站中的问题评分和排序功能。

CREATE TABLE questions (
  id INT AUTO_INCREMENT PRIMARY KEY,
  title VARCHAR(255),
  content TEXT
);

CREATE TABLE ratings (
  id INT AUTO_INCREMENT PRIMARY KEY,
  question_id INT,
  user_id INT,
  rating INT
);

<?php
// 获取当前问题的ID
$questionId = $_GET['id'];

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
  // 获取用户ID和评分值
  $userId = $_SESSION['user_id'];
  $rating = $_POST['rating'];

  // 将评分插入到数据库中
  $query = "INSERT INTO ratings (question_id, user_id, rating) VALUES ('$questionId', '$userId', '$rating')";
  // 执行插入操作

  if ($result) {
    // 评分成功，刷新页面或跳转回问题详情页
  } else {
    // 评分失败，显示错误信息
  }
}
?>

<!-- 评分组件 -->
<form action="" method="POST">
  <input type="hidden" name="rating" value="1">
  <button type="submit">赞同</button>
</form>

<form action="" method="POST">
  <input type="hidden" name="rating" value="-1">
  <button type="submit">反对</button>
</form>

<?php
// 查询问题和评分表格，并按评分值降序排列
$query = "SELECT q.id, q.title, q.content, AVG(r.rating) AS average_rating
          FROM questions q
          LEFT JOIN ratings r ON q.id = r.question_id
          GROUP BY q.id
          ORDER BY average_rating DESC";
// 执行查询操作

while ($row = mysqli_fetch_assoc($result)) {
  // 显示问题列表
  echo '<h3>' . $row['title'] . '</h3>';
  echo '<p>' . $row['content'] . '</p>';
  echo '<p>评分：' . $row['average_rating'] . '</p>';
}
?>