Question

我有一个页面，用户可以在其中选择产品（产品来自sql数据库）并输入所需数量。然后，他们查看“购物车”页面并提交订单，该订单仅向电子邮件发送详细信息。我试图在提交订单时自动更新sql数据库中的数量。

我认为我必须做类似以下的事情，但是我是php和sql的新手。我必须从数据库中提取原始数量，然后减去用户输入并显示在购物车页面上的“订购数量”，然后设置该新值。谁能阐明我如何实现这一目标？

我认为我该怎么办？：

$updquery = 'UPDATE "products" SET "Quantity"= "Quantity" - '. $product['quantity'] .' WHERE PID = '. $product['id'] .' ';

cart.php

<?php
// Initialize the session
session_start();

// Check if the user is logged in, if not then redirect him to login page
if(!isset($_SESSION["loggedin"]) || $_SESSION["loggedin"] !== true){
header("location: login.php");
exit;
}
?>

<?php
@session_start();

if(isset($_POST['logout'])) {
unset($_SESSION['shopping_cart']);

}

if(isset($_POST['submit'])) {
$email = $_POST['email'];
// Create the email and send the message
$to = 'myemail@gmail.com'; // Add your email address inbetween the '' 
replacing yourname@yourdomain.com - This is where the form will send a 
message to.
$email_subject = "Products Order - ".$_POST['email']."";
// PREPARE THE BODY OF THE MESSAGE
        $email_body = '<html><body>';
        $email_body .= '<h1 style="text-align:center;">Products List</h1>';
        $email_body .= '<table rules="all" style="border-color: #666;margin: 
 auto;" border="1" cellpadding="10">';
        $email_body .= '<tr><th colspan="2"><h3>Requested Parts</h3></th> 
</tr>';
        $email_body .= '<tr><th width="100" align="left">Product ID</th><th 
width="100" align="right">Quantity</th></tr>';

         foreach($_SESSION['shopping_cart'] as $key => $product):

         $email_body .= '<tr><td>'. $product['id'] .'</td><td 
align="right">'. $product['quantity'] .'</td></tr>';

         endforeach; 
        $email_body .= "</table>";
        $email_body .= "</body></html>";
        $headers = "From: myemail@gmail.com\n"; // This is the email address 
the generated message will be from. We recommend using something like 
noreply@yourdomain.com.
        $headers .= "Reply-To: ".$_POST['email']."\r\n";
        $headers .= "MIME-Version: 1.0\r\n";
        $headers .= "Content-Type: text/html; charset=ISO-8859-1\r\n";
        $headers .= "X-Mailer: PHP/".phpversion();   
 mail($to,$email_subject,$email_body,$headers);
unset($_SESSION['shopping_cart']);
?>
<script>
alert("Your order has been submitted")
 window.location.href = "index.php"
</script>
<?php
}
?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">


<head>
<title>Inventory Cart</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="shortcut icon" href="/icon.ico" type="image/x-icon">
<style>
*{
margin :auto;
}
table {
border-collapse: collapse;
}
th, td {
border: 1px solid #ccc;
padding: 10px;
text-align: center;
}
tr:nth-child(even) {
background-color: #eee;
}  
tr:nth-child(odd) {
background-color: #fff;
}            
</style>

</head>
<body>

<h1 style="text-align:center;">Cart</h1>
<?php  
if(!empty($_SESSION['shopping_cart'])){  ?>
    <div class="table-responsive" style="background:white;">  
    <table class="table table-responsive" id="mytable" border="1" 
align="center">  
        <tr><th colspan="2"><h3>Requested Parts</h3></th></tr>  
    <tr>  
         <th width="100" align="left">Product ID</th>  
         <th width="100" align="right">Quantity</th>  
    </tr>  
 <?php


         foreach($_SESSION['shopping_cart'] as $key => $product):
    ?>  
    <tr>  
       <td><?php echo $product['id']; ?></td>  
       <td align="right"><?php echo $product['quantity']; ?></td>  
    </tr>  
    <?php  
         endforeach;  
    ?>  


    </table>
    <div style="text-align:center;">

    <form action="" method="post">
      <input type="email" size="31" name="email" placeholder="Please enter 
your email address" required /><br>
      <input type="submit" name="submit" value="Submit" id="btnSubmit"/>
    </form>
    <form action="" method="post">
      <input type="submit" name="logout" value="Clear" id="btnClear" />

    </form>

    </div>
     </div>
    <?php  
 }
    else{
        ?>
        <script>
            alert("Cart is empty")
            window.location.href = "index.php"
        </script>
        <?php
    }
    ?>
    <br><br>
 </body>
</html>

Answer 1

您提供了自己的答案（查询）：

1）在脚本的开头设置mysql连接：

$con=mysqli_connect("localhost","my_user","my_password","my_db");
// Check connection
if (mysqli_connect_errno()){
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

2）在foreach中，添加查询以在将每种产品的数量添加到电子邮件中时更新它们的数量。成为：

foreach($_SESSION['shopping_cart'] as $key => $product):
   $email_body .= '<tr><td>'. $product['id'] .'</td><td align="right">'. $product['quantity'] .'</td></tr>';
   mysqli_query($con,'UPDATE products SET Quantity = Quantity - '. $product['quantity'] .' WHERE PID = '. $product['id'] .' ');
endforeach; 
mysqli_close($con);

从购物车页面使用PHP更新SQL数量

1 个答案: