PHP foreach 循环中条件语句未按预期处理多条记录的常见原因与解决方案

// 假设这是从文件读取并处理后的$orders数组
// 注意：这里以customer_id作为主键，导致数据覆盖
$orders = [
    'customer_101' => [
        'order_id' => 'ORD001',
        'item' => 'Laptop',
        'amount' => 1200
    ],
    'customer_102' => [
        'order_id' => 'ORD002',
        'item' => 'Mouse',
        'amount' => 25
    ],
    'customer_101' => [ // 错误！这个条目会覆盖上面customer_101的条目
        'order_id' => 'ORD003',
        'item' => 'Keyboard',
        'amount' => 75
    ]
];

// 实际$orders数组最终只会是：
// $orders = [
//     'customer_101' => [
//         'order_id' => 'ORD003', // 只有最后一条订单数据被保留
//         'item' => 'Keyboard',
//         'amount' => 75
//     ],
//     'customer_102' => [
//         'order_id' => 'ORD002',
//         'item' => 'Mouse',
//         'amount' => 25
//     ]
// ];

// 假设这是从文件读取并处理后的$orders数组
// 以唯一的order_id作为主键，customer_id作为订单数据内部的一个属性
$orders = [
    'ORD001' => [
        'customer_id' => 'customer_101',
        'item' => 'Laptop',
        'amount' => 1200
    ],
    'ORD002' => [
        'customer_id' => 'customer_102',
        'item' => 'Mouse',
        'amount' => 25
    ],
    'ORD003' => [
        'customer_id' => 'customer_101', // 多个订单可以指向同一个客户ID
        'item' => 'Keyboard',
        'amount' => 75
    ],
    'ORD004' => [
        'customer_id' => 'customer_101',
        'item' => 'Monitor',
        'amount' => 300
    ]
];

<?php

// 模拟从文件读取的订单数据，使用正确的结构
function readOrdersFromFile($filename) {
    // 实际应用中，这里会解析orders.txt文件内容
    // 并构建成以下示例的数组结构
    return [
        'ORD001' => ['customer_id' => 'customer_101', 'item' => 'Laptop', 'amount' => 1200],
        'ORD002' => ['customer_id' => 'customer_102', 'item' => 'Mouse', 'amount' => 25],
        'ORD003' => ['customer_id' => 'customer_101', 'item' => 'Keyboard', 'amount' => 75],
        'ORD004' => ['customer_id' => 'customer_103', 'item' => 'Webcam', 'amount' => 50],
        'ORD005' => ['customer_id' => 'customer_101', 'item' => 'Monitor', 'amount' => 300],
    ];
}

// 模拟客户数据
$customers = [
    'customer_101' => ['name' => 'Alice', 'email' => 'alice@example.com'],
    'customer_102' => ['name' => 'Bob', 'email' => 'bob@example.com'],
    'customer_103' => ['name' => 'Charlie', 'email' => 'charlie@example.com'],
];

if ($_SERVER['REQUEST_METHOD'] == 'GET') {
    if (isset($_GET['customer'])) {
        $requestedCustomerId = $_GET['customer'];

        // 确保请求的客户ID存在
        if (!isset($customers[$requestedCustomerId])) {
            echo "客户ID '{$requestedCustomerId}' 不存在。";
            exit;
        }

        $requestedCustomer = $customers[$requestedCustomerId];
        $orders = readOrdersFromFile('orders.txt'); // 获取所有订单

        echo "<h2>客户: " . htmlspecialchars($requestedCustomer['name']) . " 的订单</h2>";
        echo "<table border='1'>";
        echo "<thead><tr><th>订单ID</th><th>商品</th><th>金额</th></tr></thead>";
        echo "<tbody>";

        $foundOrders = false;
        foreach ($orders as $orderId => $orderData) {
            // 检查订单数据中内嵌的customer_id是否与请求的客户ID匹配
            if (isset($orderData['customer_id']) && $orderData['customer_id'] == $requestedCustomerId) {
                echo "<tr>";
                echo "<td>" . htmlspecialchars($orderId) . "</td>";
                echo "<td>" . htmlspecialchars($orderData['item']) . "</td>";
                echo "<td>$" . htmlspecialchars(number_format($orderData['amount'], 2)) . "</td>";
                echo "</tr>";
                $foundOrders = true;
            }
        }

        if (!$foundOrders) {
            echo "<tr><td colspan='3'>没有找到该客户的订单。</td></tr>";
        }
        echo "</tbody>";
        echo "</table>";

    } else {
        echo "请在URL中指定一个客户ID，例如：?customer=customer_101";
    }
}
?>