使用 meekro 库对可用库存数量求和

Sum available quantities in stock with meekro library

Table: stock

╔═════════════╦═══════════════════╦══════════╦═══════════════╗
║ id          ║ product_id        ║ store_id ║ quantity      ║
╠═════════════╬═══════════════════╬══════════╬═══════════════╣
║  1          ║ 1                 ║   1      ║10             ║
║  2          ║ 1                 ║   2      ║20             ║
║  3          ║ 2                 ║   1      ║10             ║
║  4          ║ 2                 ║   2      ║20             ║
║  5          ║ 2                 ║   3      ║30             ║
║  6          ║ 3                 ║   1      ║10             ║
║  7          ║ 3                 ║   2      ║20             ║
╚═════════════╩═══════════════════╩══════════╩═══════════════╝

目前这是我的查询:

<?php
$QueryStock = DB::query("SELECT * FROM stock WHERE product_id = 2");
foreach ($QueryStock as $Stock) {
    echo $Stock['quantity']."<br>";
}
?>

我得到:

10
20
30

我正在使用 meekro 库,我正在尝试获取我的产品数量的总和,你知道我应该如何求和以获得所有商店的总数量吗?

您可以对所有数量求和并得出最终结果。在那种情况下,之后使用的 foreach 语句变得无用:

SELECT sum(quantity) as total FROM stock WHERE product_id = 2;