php - 显示随机问题

Question

我正在设计一个测试，我想随机显示问题。我的数据库中有 50 个问题。为此，我编写了以下代码:

$singleSQL = mysql_query("SELECT * FROM questions WHERE id='$question' ORDER BY Rand()"); 

        while($row = mysql_fetch_array($singleSQL)){
            $id = $row['id'];
            $thisQuestion = $row['question'];
            $type = $row['type'];
            $question_id = $row['question_id'];
            $q = '<h2>'.$thisQuestion.'</h2>';
            $sql2 = mysql_query("SELECT * FROM answers WHERE question_id='$question' ORDER BY rand()");
            while($row2 = mysql_fetch_array($sql2)){
                $answer = $row2['answer'];
                $correct = $row2['correct'];
                $answers .= '<label style="cursor:pointer;"><input type="radio" name="rads" value="'.$correct.'">'.$answer.'</label> 
                <input type="hidden" id="qid" value="'.$id.'" name="qid"><br /><br />
                ';

            }
            $output = ''.$q.','.$answers.',<span id="btnSpan"><button onclick="post_answer()">Submit</button></span>';
            echo $output;
           }

第一行中的 rand() 函数不适用于问题，但相同的函数适用于答案(MCQ 的选项随机出现)。另外，当我在第一行中更改 sql 查询时，我收到错误:

警告:

mysql_fetch_array() expects parameter 1 to be resource
boolean given in C:\xampp\htdocs\questions.php on line 36
undefined.

不知道怎么了!!请帮助我..!!

Answer 1

第一个查询中的 WHERE id = '$question' 子句使其仅返回与该 ID 匹配的单个问题，而不是所有问题。您需要删除它。

$singleSQL = mysql_query("SELECT * FROM questions ORDER BY Rand()"); 

在循环内部，您在第二个查询中使用了错误的变量。应该是:

$sql2 = mysql_query("SELECT * FROM answers WHERE question_id='$question_id' ORDER BY rand()");