使用 PHP 開發知識問答網站中的問題答案採納和推薦功能。

CREATE TABLE questions (
    id INT PRIMARY KEY AUTO_INCREMENT,
    title VARCHAR(255),
    content TEXT,
    owner_id INT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE answers (
    id INT PRIMARY KEY AUTO_INCREMENT,
    question_id INT,
    content TEXT,
    owner_id INT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE accepted_answers (
    question_id INT PRIMARY KEY,
    answer_id INT
);

<?php
// 获取问题 ID
$questionId = $_GET['id'];

// 获取问题信息
$questionQuery = "SELECT * FROM questions WHERE id = :id";
$questionStmt = $pdo->prepare($questionQuery);
$questionStmt->bindParam(':id', $questionId, PDO::PARAM_INT);
$questionStmt->execute();
$question = $questionStmt->fetch(PDO::FETCH_ASSOC);

// 显示问题标题和内容
echo "<h1>" . $question['title'] . "</h1>";
echo "<p>" . $question['content'] . "</p>";

// 获取问题的回答信息
$answersQuery = "SELECT * FROM answers WHERE question_id = :question_id";
$answersStmt = $pdo->prepare($answersQuery);
$answersStmt->bindParam(':question_id', $questionId, PDO::PARAM_INT);
$answersStmt->execute();
$answers = $answersStmt->fetchAll(PDO::FETCH_ASSOC);

// 显示回答列表
foreach ($answers as $answer) {
    echo "<div>";
    echo "<p>" . $answer['content'] . "</p>";

    // 检查答案是否被采纳
    if ($answer['id'] === $question['accepted_answer_id']) {
        echo "<span>已采纳</span>";
    } else {
        // 显示采纳按钮
        echo "<a href='accept-answer.php?question=" . $questionId . "&answer=" . $answer['id'] . "'>采纳该答案</a>";
    }

    echo "</div>";
}
?>

<?php
// 获取问题 ID 和答案 ID
$questionId = $_GET['question'];
$answerId = $_GET['answer'];

// 将答案 ID 更新为被采纳
$acceptAnswerQuery = "UPDATE accepted_answers SET answer_id = :answer_id WHERE question_id = :question_id";
$acceptAnswerStmt = $pdo->prepare($acceptAnswerQuery);
$acceptAnswerStmt->bindParam(':answer_id', $answerId, PDO::PARAM_INT);
$acceptAnswerStmt->bindParam(':question_id', $questionId, PDO::PARAM_INT);
$acceptAnswerStmt->execute();

// 返回问题详情页
header("Location: question.php?id=" . $questionId);
?>