在另一个查询中使用查询结果 [英] Using a query result in another query

问题描述

这是我的第一个查询，我想将提取的多个itemID用于另一个查询.

This is my first query, i want to use the multiple itemID's extracted for another query.

$conn = new mysqli(server, dbuser, dbpw, db);
$email = $_GET['email'];
$querystring = "SELECT itemID from mycart where email = '".$email."' ";
$result = $conn->query($querystring);
$rs = $result->fetch_array(MYSQLI_ASSOC);

需要的第二个查询

$query = "SELECT * from CatalogueItems where itemID = '".$itemID."'";

我如何运行这两个查询?

How do i make these 2 query run?

推荐答案

首先，您的代码向相关的攻击.请学习使用准备好的语句

现在，从查询的角度来看，您可以利用JOIN使其成为单个查询:

Now, from a query point of view, you can rather utilize JOIN to make this into a single query:

SELECT ci.* 
FROM CatalogueItems AS ci
JOIN mycart AS mc ON mc.itemID = ci.itemID 
WHERE mc.email = $email  /* $email is the input filter for email */

利用MySQLi库的预处理语句的PHP代码如下:

PHP code utilizing Prepared Statements of MySQLi library would look as follows:

$conn = new mysqli(server, dbuser, dbpw, db);
$email = $_GET['email'];

$querystring = "SELECT ci.* 
                FROM CatalogueItems AS ci
                JOIN mycart AS mc ON mc.itemID = ci.itemID 
                WHERE mc.email = ?";  // ? is the placeholder for email input

// Prepare the statement
$stmt = $conn->prepare($querystring);

// Bind the input parameters
$stmt->bind_param('s', $email);  // 's' represents string input type for email

// execute the query
$stmt->execute();

// fetch the results
$result = $stmt->get_result();
$rs = $result->fetch_array(MYSQLI_ASSOC);

// Eventually dont forget to close the statement
// Unless you have a similar query to be executed, for eg, inside a loop
$stmt->close();

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