PHP在string2中查找string1，其中string1派生自MySQL表

<?php
// 连接数据库
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "my_database";

$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 查询关键词
$sql = "SELECT keywords FROM my_table";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        $keywords[] = $row["keywords"];
    }
} else {
    echo "0 结果";
}

$conn->close();

// 假设string2是我们想要搜索的长文本
$string2 = "这是一段包含多个关键词的文本...";

// 在string2中查找每个关键词
foreach ($keywords as $keyword) {
    if (strpos($string2, $keyword) !== false) {
        echo "找到关键词: " . $keyword . "<br>";
    } else {
        echo "未找到关键词: " . $keyword . "<br>";
    }
}
?>