所以我有一個如下所示的請求響應$json='[ {"item_cat":"Stationary","items":[{"item_name":"A4 Paper","qty":"2"},{"item_name":"Test Paper","qty":"6"}],"total":"2"},{"item_cat":"Computer Accessory ","items":[{"item_name":"Power pack","qty":"2"}],"total":"1"},{"item_cat":"Material","items":[{"item_name":"T-Shirt","qty":"3"},{"item_name":"Cap","qty":"5"}],"total":"2"}]';我正在嘗試獲取每個 item_name 和 qty，以便我可以使用它們來操作我的數據庫。這是我所做的$data = json_decode($json, true);$len = count($data);    for($i =0; $i< $len; $i++){            $item_length = count($data[$i]['items']);        for($c=0; $c < $item_length; $c++){            foreach ($data[$i]['items'][$c] as $key => $value ) {                $qty = '';                if($key == "qty"){                    $qty = $data[$i]['items'][$c];                    }                if($key == 'item_name'){                    $item_name = "$value";                    }                    $sql= $db->query("SELECT `stock` from `inventory` WHERE `item_name` = '$item_name'");                    while ($sql1 = $sql->fetch_assoc()) {                            $stock = $sql1['stock'];                  }                    if($stock > $qty ){                        $stock_balance = $stock - $qty;                    $quantity = (int)$qty;                         $db->query("UPDATE `inventory` SET `stock` =  (`stock` - '$quantity')   WHERE `item_name` = '$item_name'");                    }else{                        echo "<h3> This Operation Not Allowed: Stock Balance Is Less Than The Request <h3>";                    }                }            }        }遇到非數字值，這是 $qty 的結果，因為我無法僅返回 qty 值。我嘗試過其他幾種方法。我真的很累了。如果有任何幫助，我將不勝感激。干杯!