从MySQL数据库中选择随机问题; "正确答案"搞砸了

Question

我正在使用PHP和MYSQL构建一个简单的测验程序.

测验旨在一次显示一个问题; 问题是多项选择(每个问题有4个可能的答案)

如果玩家选择了正确的玩家,他会进入下一个问题; 如果他选错了,测验就结束了.

首先,我设计了如下测验:

(1)创建了一个数据库表,其中包含1500个问题.该表包含以下列:

ID (primary key)
QUESTION (the question itself)
A1 (first answer)
A2 (second answer)
A3 (third answer)
A4 (fourth answer)
CORRECT  (the correct answer --- which is one of the above A1 to A4)

(2)然后,我的PHP代码被设计为以SEQUENTIAL顺序逐个选择问题(使用ID作为参考).

因此,当用户开始播放时,他从问题1开始,然后问题2等等.

(3)为了使它更有趣,当用户在我的测验网站上注册为播放器时,我向数据库(begin_id)添加了一个额外的列,其默认值为"1".每次用户回答问题时,都会使用该问题的"ID"更新此列.意思是,它记录用户回答的最后一个问题(无论是错误还是正确).这样:下次用户登录并播放测验时,他不会从问题1开始.相反,他从列表中的NEXT问题开始.(意思是,用户永远不会看到同一个问题两次!)

这是代码:

// Query database
$get_question = "SELECT * from questions_table where id = $begin_id";
$result_get_question = mysqli_query($conn, $get_question);
$row_get_question = mysqli_fetch_array($result_get_question);

// Assign database response to variables
$question = $row_get_question['question'];
$a1 = $row_get_question['a1'];
$a2 = $row_get_question['a2'];
$a3 = $row_get_question['a3'];
$a4 = $row_get_question['a4'];
$correct = $row_get_question['correct'];

// Check user answer
if (isset($_POST['submit'])) {   
    $selected_radio = $_POST['response'];

    if ($selected_radio == $correct)
        echo "THAT ANSWER IS CORRECT";
    else
        echo "THAT ANSWER IS WRONG!";
}

而且,一切都很美妙!!

现在,我决定让它更"高效"; 我没有按顺序选择问题,而是决定简单地修改我的PHP-SELECT语句,随意选择问题.

这很容易,特别是因为有很多在线教程如何完成.

这是我使用的代码(最简单的代码):

SELECT * from questions_table order by rand() limit 1;

就选择随机问题而言,这是有效的.但是,有些事情是错误的:无论用户选择什么答案,总是错误的答案!

出于某种原因,从数据库中选择随机问题已经弄乱了我的PHP代码中的" 正确答案/错误答案 "逻辑.

不知道出了什么问题.

UPDATE

   $get_question = "SELECT * from questions_table where id = $begin_id";

   $result_get_question = mysqli_query($conn,$get_question);

   $row_get_question = mysqli_fetch_array($result_get_question);  

   $question_id = $row_get_question['question_id'];

   $question = $row_get_question['question'];

   $a1 = $row_get_question['a1'];

   $a2 = $row_get_question['a2'];

   $a3 = $row_get_question['a3'];

   $a4 = $row_get_question['a4'];

   $correct = $row_get_question['correct'];

  <br>

  <form method ="post" action ="">

  <input type="radio" name="response" value="<?=$a1?>"><?=$a1?><br>

  <input type="radio" name="response" value="<?=$a2?>"><?=$a2?><br>

  <input type="radio" name="response" value="<?=$a3?>"><?=$a3?><br>

  <input type="radio" name="response" value="<?=$a4?>"><?=$a4?><br>
          <input type="hidden" name="question_id" value="<?= echo $question_id?>" 
    />        <br>

  <Input type = "submit" Name = "submit" Value = "Answer">        </form>

Answer 1

当您向用户提出问题时,会从数据库中随机选择一个问题.

然后,用户提交您的表单,随机选择另一个问题,这是您用来检查答案的问题,而不是您向用户询问的问题.

您需要在表单中添加一个包含问题ID的隐藏输入

<input type="hidden" name="question_id" value="<?php echo $question_id ?>" />

然后当您检查答案时,请务必从数据库中获取正确的问题

代码看起来像这样

<?php

// Check user answer for previous question
if (isset($_POST['submit'])) {   
    // Retrieve the id of the question you asked
    $previous_question_id = (int) $_POST['question_id']; // cast to integer to prevent sql injection.

    // Query database
    $get_question = "SELECT * from questions_table where id = $previous_question_id";
    $result_get_question = mysqli_query($conn, $get_question);
    $row_get_question = mysqli_fetch_array($result_get_question);

    // Assign database response to variables
    $correct = $row_get_question['correct'];
    $selected_radio = $_POST['response'];

    if ($selected_radio == $correct)
        echo "THAT ANSWER IS CORRECT";
    else
        echo "THAT ANSWER IS WRONG!";
}


// Load new question to ask to the user
$get_question = "SELECT * from questions_table order by rand() limit 1";
$result_get_question = mysqli_query($conn,$get_question);
$row_get_question = mysqli_fetch_array($result_get_question);  

// assign thing we want to print in the template to variable
$question_id = $row_get_question['question_id'];
$question = $row_get_question['question'];
$a1 = $row_get_question['a1'];
$a2 = $row_get_question['a2'];
$a3 = $row_get_question['a3'];
$a4 = $row_get_question['a4'];

?>

<PASTE YOUR TEMPLATE HERE>