PHP到GEOJSON数组不循环MYSQL数据库中的行

<?php
// 连接到MYSQL数据库
$servername = "数据库服务器地址";
$username = "数据库用户名";
$password = "数据库密码";
$dbname = "数据库名";

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

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

// 执行查询语句
$sql = "SELECT * FROM 表名";
$result = $conn->query($sql);

// 将查询结果转换为GEOJSON数组
$features = array();

if ($result->num_rows > 0) {
    while ($row = $result->fetch_assoc()) {
        $geometry = array(
            'type' => 'Point',
            'coordinates' => array($row['longitude'], $row['latitude'])
        );

        $properties = array(
            'id' => $row['id'],
            'name' => $row['name']
        );

        $feature = array(
            'type' => 'Feature',
            'geometry' => $geometry,
            'properties' => $properties
        );

        array_push($features, $feature);
    }
}

$geojson = array(
    'type' => 'FeatureCollection',
    'features' => $features
);

// 输出GEOJSON数组
echo json_encode($geojson);

// 关闭数据库连接
$conn->close();
?>