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我现在有这个循环，但它涉及调用数据库 5 到 10 次。有没有一种方法我可以只调用一次，也许是一个 while 循环，或者任何其他任何人都可以想到的替代方法，因为它会减慢操作速度。

foreach($_SESSION['cart_array'] as $each_item) {
   $item_id = $each_item['item_id'];
   $each_quantity = $each_item['quantity'];
   $item_qry = mysql_query("SELECT * FROM `products` WHERE `products_id`=$item_id");
   $item_row = mysql_fetch_assoc($item_qry);
   $product_price = $item_row['products_price'];
   $total_price += $product_price * $each_quantity;
}
4

2 回答 2

2

是的，您可以一次选择所有行：

$total_price = 0;
if (!empty($_SESSION["cart_array"])) {
    $query = "SELECT `products_price`, `products_id` FROM `products` WHERE `products_id` IN (";
    $query .= implode(", ", array_map(function ($item) { return $item["item_id"]; }, $_SESSION['cart_array']));
    $query .= ")";
    $result = mysql_query($query);

    while ($row = mysql_fetch_assoc($result))
        $items[$row["products_id"]] = $row["products_price"];

    foreach ($_SESSION["cart_array"] as $item)
        $total_price += $item["quantity"] * $items[$item["item_id"]];
}
于 2013-07-25T23:58:34.340 回答
0

一种查询解决方案：

$item_id_array = array();
$item_to_quant = array();
foreach($_SESSION['cart_array'] as $each_item)
{
    $item_id_array[] = $each_item['item_id'];

    $item_to_quant[$each_item['item_id']] = $each_item['quantity'];
}

$item_qry = mysql_query("SELECT * FROM `products` WHERE `products_id` IN (" . implode(',', $item_id_array) . ")");


$total_price = 0;
$results     = array();

while ($item_row = mysql_fetch_assoc($item_qry))
{
    //add total price to result array
    $item_row['total_items_price'] = $item_row['products_price'] * $item_to_quant[$item_row['products_id']];

    $results[] = $item_row;

    $total_price += $item_row['total_item_price'];
}

您会得到结果数组和总价变量作为结果。

于 2013-07-26T00:15:43.197 回答