<form action="search.php" method="GET">
    <input type="text" name="keyword" placeholder="请输入搜索关键词" required>
    <button type="submit">搜索</button>
</form>

$keyword = trim($_GET['keyword'] ?? '');
if (empty($keyword) || strlen($keyword) < 2) {
    echo "请输入有效的关键词";
    exit;
}

try {
    $pdo = new PDO("mysql:host=localhost;dbname=your_db", "username", "password");
    $stmt = $pdo->prepare("SELECT id, title, content, created_time 
                           FROM articles 
                           WHERE title LIKE ? OR content LIKE ?
                           ORDER BY created_time DESC");
    $searchTerm = "%{$keyword}%";
    $stmt->execute([$searchTerm, $searchTerm]);
    $results = $stmt->fetchAll(PDO::FETCH_ASSOC);
} catch (PDOException $e) {
    die("数据库错误：" . $e->getMessage());
}

function highlight($text, $word) {
    return str_ireplace($word, "<strong style='color:red'>$word</strong>", $text);
}

if (count($results) > 0) {
    echo "<p>共找到 " . count($results) . " 条结果：</p>";
    foreach ($results as $row) {
        echo "<h3>" . htmlspecialchars(highlight($row['title'], $keyword)) . "</h3>";
        echo "<p>" . htmlspecialchars(mb_substr(highlight($row['content'], $keyword), 0, 150)) . "...</p>";
        echo "<small>发布时间：" . $row['created_time'] . "</small><hr>";
    }
} else {
    echo "未找到相关结果。";
}