Php 如何从下拉列表中捕获主键并作为另一个表的外键插入？

请帮我把一些东西注释掉以便测试，但没有任何效果

<?php
    //retrieve the data sent in  the POST request

         $yourDateOrdered =$_POST["DateOrdered"];
         $yourDueDate = $_POST["DueDate"];
         if(isset($_POST["CompanyName"])){$yourCompanyName = $_POST["CompanyName"];}


    //Validate the fields   
        if ($yourDateOrdered=="" || $yourDateOrdered==null){
                $err= $err."Please enter the date the purchase order was made<br>";
             }  

        if ($yourDueDate=="" || $yourDueDate==null){
            $err= $err. "Please enter a date when the item is required<br>";
            }

        //if ($yourCompanyName=="" || $yourCompanyName==null){
            //$err= $err."Please enter the customer name<br>";
             //}            

    //Connect to the server and select database
        include("dbConnection.php");

    //define sql query to execute on the database
        $Query1="INSERT INTO orders(CompanyName, DateOrdered, DueDate)
        VALUES ('$yourCompanyName','$yourDateOrdered', '$yourDueDate')";

        //execute query
        //$result = mysql_query($Query1);

            //echo("The following order has been added");


    //result of the action stored in $Result
        $Result = mysql_query($Query1);

        if($Result){
            echo 'Order entered';
            echo Header ("Location:orderformitem.php");

            } 

    //Close the connection
        mysql_close($con);  

    //Check if query executed successfully and forward the user to an appropriate location
        //if($queryResult){
            //echo "Order save <br>";
                //Header ("Location:../PHP/orderformitem.php");
                //}
?>

您确实需要学习如何调试。首先，注释掉标题“Location…”；行，以捕获错误

添加错误报告全部；和显示错误1；在文件顶部，查看任何错误

让我们看看var_dump$_POST是否所有变量都正确

如果您想要正确的日期，请执行日期验证

转储查询，并尝试直接在sql中运行它

不要使用mysql函数，因为它们已被弃用。改用mysqli或PDO

转义您的数据，以避免sql注入

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您是否考虑过取消对您评论的内容的评论以使其恢复工作状态？我不明白这个问题和测试目的之间的联系？它一直告诉我我的yourCompanyName是一个未定义的变量