从购物车检索和回显 'products' 的简单 PHP 请求不起作用？

Question

正在尝试使用 while loop 从数据库中回显 prod_qty 和 prod_desc 字段。 没有错误。我也尝试过使用 foreach loop，正如您在代码中看到的那样，但是 它没有显示任何内容。

这是 cart.php 文件：

    <?php
// 1. Establish a connection using three functions: 1. mysqli_connect() 2. mysqli_connect_errno() 3. mysqli_connect_error()
    $dbhost = "localhost";
    $dbuser = "root";
    $dbpass = "";
    $dbname = "shoppingcart";

    $connection = mysqli_connect($dbhost, $dbuser, $dbpass, $dbname); 

    // Test if connection occured
    if(mysqli_connect_errno()) {
        die("Database connection failed " . mysqli_connect_error() . "( " . mysqli_connect_errno() . " )");
        }    


    // Show the products by performing a query to database.
    $query = "SELECT prod_desc, prod_qty FROM cart WHERE prod_id = 1 AND prod_id = 2 AND prod_id = 3 ";

    $result = mysqli_query($connection, $query);

    while($cart = mysqli_fetch_assoc($result)) {
        echo $cart["prod_qty"];
        echo $cart["prod_desc"];

    }

    /*if($result) {

        foreach ($result as $cart ) {
            echo $cart["prod_qty"];
            echo $cart["prod_desc"];

        }

        } */

?>

这是我的数据库结构：

我确定我犯了一个愚蠢的错误，因为我没有发现任何错误！大家有什么想法吗？

Answer 1

不能对同一列使用 AND。

改变这个：

$query = "SELECT prod_desc, prod_qty FROM cart WHERE prod_id = 1 AND prod_id = 2 AND prod_id = 3 ";

至

$query = "SELECT prod_desc, prod_qty FROM cart WHERE prod_id = 1 OR prod_id = 2 OR prod_id = 3 ";

Answer 2

如果你想获得 prod_id 1 或 2 或 3 的记录，你可以使用 in 如下：

$query = "SELECT prod_desc, prod_qty FROM cart WHERE prod_id in (1, 2, 3 )";

从购物车检索和回显 'products' 的简单 PHP 请求不起作用？

Simple PHP request to retrieve and echo 'products' from cart not working?

php

mysql

foreach

shopping-cart

while-loop