用php处理mysql数组

您应该使用group-by.修改查询如下：

$sql =  "select c.customer_id, c.firstname, c.lastname, 
                   o.order_id, o.date_added, 
                   op.name, sum(op.quantity)
            from `" . DB_PREFIX . "customer` c
            inner join `" . DB_PREFIX . "order` o on o.customer_id = c.customer_id
            inner join `" . DB_PREFIX . "order_product` op on o.order_id = op.order_id
group by c.customer_id, op.name
";

检查更新答案：

$sql =  "select c.customer_id, c.firstname, c.lastname, op.name, sum(op.quantity)
                from `" . DB_PREFIX . "customer` c
                inner join `" . DB_PREFIX . "order_product` op on o.order_id = op.order_id
    group by c.customer_id, op.name
    ";

更新2:

$sql =  "select *, sum(quantity)  from (select c.customer_id, c.firstname, c.lastname, op.quantity     from `" . DB_PREFIX . "customer` c
                inner join `" . DB_PREFIX . "order` o on o.customer_id = c.customer_id
                inner join `" . DB_PREFIX . "order_product` op on o.order_id = op.order_id
) result
    group by result.customer_id, result.name
    ";

$customers = array();
foreach ($data as $key => $values) {
    if (!isset($customers[$values['id']])) {
        $name = $values['firstname'].' '. $values['lastname'];  
        $customers[$values['id']]['name'] = $name;
    } else {
        $customers[$values['id']]['order'][] = $values['name']. ' '. $values['quantity'];
    }
}
foreach ($customers as $customer) {
    $string = $customer['name'] . '<br/>';
    foreach ($customer['order'] as $oder) {
        $string .= $oder. '<br/>';
    }
    print $string;
} 

可能是您正在为客户下订单时选择的每个产品运行插入语句，或者您的数据库没有规范化。

我的建议是维护一个购物车，买家可以在其中添加商品，然后在确认订单时生成一个逗号或分号分隔的商品列表，并将该字符串存储在数据库列中。当你稍后取回它时，你会得到一个字符串，你可以分解它来获得独立的元素。

更好的方法是将itemid存储为串联字符串，而不是它们的名称。这是您的所有订单详细信息，属于该订单的项目将在一行中，而不是同一订单的多行中。

你的数据库表可能看起来像

customerid orderid项ordertime1 3 23,6,35,41201201-17 11:22:30

当您分解包含该购买中物品id的物品字符串后，您将获得一个物品id的数组

[23，6，35，41]

如果你也想存储像（ipod x 3）这样的项目数量，你可以将项目字符串存储为

itemid，quantily；itemid，数量；itemid，数量