PHP将嵌套的json保存到mysql数据库

<?php
// 连接到数据库
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database";

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

// 检查连接是否成功
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 准备JSON数据
$data = array(
    "name" => "John Doe",
    "age" => 30,
    "address" => array(
        "street" => "123 Main St",
        "city" => "New York",
        "state" => "NY"
    )
);

// 将JSON数据转换为字符串
$jsonData = json_encode($data);

// 插入数据到数据库
$sql = "INSERT INTO json_data (data) VALUES ('$jsonData')";

if ($conn->query($sql) === TRUE) {
    echo "数据插入成功";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}

// 查询JSON数据
$sql = "SELECT data FROM json_data";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while ($row = $result->fetch_assoc()) {
        // 将JSON字符串转换为PHP数组
        $jsonData = json_decode($row["data"], true);
        
        // 访问数组中的数据
        echo "姓名: " . $jsonData["name"] . "<br>";
        echo "年龄: " . $jsonData["age"] . "<br>";
        echo "地址: " . $jsonData["address"]["street"] . ", " . $jsonData["address"]["city"] . ", " . $jsonData["address"]["state"] . "<br>";
    }
} else {
    echo "0 结果";
}

$conn->close();
?>