php - 下单管理逻辑

Question

我目前正在尝试形成我下订单的逻辑，如果订单与当前库存相加时超出了容量，则会出现相应的消息。此外，如果有传入订单，则在添加新订单时，它们不能超过与未决传入订单以及当前可用库存相加的容量。但是，我的问题是，无论我投入多少，它都会一直显示我的“下订单库存量已超出容量”。验证消息。我围绕这个功能的逻辑是错误的吗？谢谢。

if(isset($_POST['addBtn'])){  
        $brand = $_POST['brand'];
        $modelName = $_POST['model_name'];
        $session = $_SESSION['username'];
        $station = 'At Factory';
        $progress = 'Awaiting';
        $status = 'Awaiting';
        $handler = 'Awaiting';
        $request = '-';
        $stock = $_POST['stock'];
        $incoming = '0';
        $date = date('Y-m-j H:i:s', time());
        $stock = $_POST['stock'];
        $incoming = '0';


        $sql2 = "SELECT o.stock,m.current,m.capacity FROM orders o
                 INNER JOIN models m ON o.model_id=m.model_id
                 WHERE o.incoming = 0";
        $result2 = $conn->query($sql2);
        if(!$result2) die($conn->error);
        $rows = $result2->num_rows;

        $stok = $rows['stock'];
        $cu = $rows['current'];
        $ca = $rows['capacity'];

        if(($stock+$cu)>$ca){
?>
            <div class="alert alert-danger alert-dismissible" role="alert">
                <button type="button" class="close" data-dismiss="alert" aria-label="Close"><span aria-hidden="true">&times;</span></button>
                <strong id="alert2">Error! </strong>Placed order stock amount has exceeded capacity.
            </div>
<?php
        }elseif(($stok+$stock+$cu)>$ca){
?>
            <div class="alert alert-danger alert-dismissible" role="alert">
                <button type="button" class="close" data-dismiss="alert" aria-label="Close"><span aria-hidden="true">&times;</span></button>
                <strong id="alert2">Error! </strong>Pending incoming stocks has exceeded capacity.
            </div>
<?php
        }else{

        $query = "INSERT INTO orders(brand,model_id,station,progress,status,editor,time_ordered,admin,request) VALUES ('".$brand."','".$modelName."','".$station."','".$progress."','".$status."','".$handler."','".$date."','".$session."','".$request."')"; 
   }
}

Answer 1

我相信您的 SQL 中需要另一个 WHERE 子句来根据您的模型选择订单。

例子:

$sql2 = "SELECT SUM(o.stock) as stock_sum, m.current, m.capacity FROM orders o
INNER JOIN models m ON o.model_id=m.model_id
WHERE o.incoming = 0 AND m.model_id = $modelName";

但是如果没有订单可能会出错。例如 $cu 和 $ca 可能是空的，因为您是通过加入订单和模型来获得这些值的。

一个很好的建议是使用单独的 SQL 来检索股票总和，并使用另一个 SQL 来检索模型详细信息。