Question

我试图从我的sql表中获取随机问题.rand（）函数无效。 “答案”的rand（）函数正在运行，但不适用于“问题”行。我哪里错了？。任何人都可以解决这个问题吗？

index.php

<?php 

    $msg = "";
    if(isset($_GET['msg'])){
        $msg = $_GET['msg'];
        $msg = strip_tags($msg);
        $msg = addslashes($msg);
    }
    ?>
    <!doctype html>
    <html lang="en">
    <head>
    <meta charset="utf-8">
    <title>Quiz Tut</title>
    <script>
    function startQuiz(url){
        window.location = url;
    }
    </script>
    </head>
    <body>
    <?php echo $msg; ?>
    <h3>Click below when you are ready to start the quiz</h3>
    <button onClick="startQuiz('quiz.php?question=1')">Click Here To Begin</button>
    </body>
    </html>

questions.php

<?php 

session_start();
require_once("scripts/connect_db.php");
$arrCount = "";
if(isset($_GET['question'])){
    $question = preg_replace('/[^0-9]/', "", $_GET['question']);
    $output = "";
    $answers = "";
    $q = "";
    $sql = mysql_query("SELECT id FROM questions");
    $numQuestions = mysql_num_rows($sql);
    if(!isset($_SESSION['answer_array']) || $_SESSION['answer_array'] < 1){
        $currQuestion = "1";
    }else{
        $arrCount = count($_SESSION['answer_array']);
    }
    if($arrCount > $numQuestions){
        unset($_SESSION['answer_array']);
        header("location: index.php");
        exit();
    }
    if($arrCount >= $numQuestions){
        echo 'finished|<p>There are no more questions. Please enter your first and last name and click next</p>
                <form action="userAnswers.php" method="post">
                <input type="hidden" name="complete" value="true">
                <input type="text" name="username">
                <input type="text" name="email">
                <input type="submit" value="Finish">
                </form>';
        exit();
    }
    $singleSQL = mysql_query("SELECT * FROM questions WHERE id='$question' order by RAND() LIMIT 1");

        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'];
                $answers .= '<label style="cursor:pointer;"><input type="checkbox" name="rads" value="'.$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;
           }
        }


?>

quiz.php

<?php

session_start();
if(isset($_GET['question'])){
    $question = preg_replace('/[^0-9]/', "", $_GET['question']);
    $next = $question + 1;
    $prev = $question - 1;
    if(!isset($_SESSION['qid_array']) && $question != 1){
        $msg = "Sorry! No cheating.";
        header("location: index.php?msg=$msg");
        exit();
    }
    if(isset($_SESSION['qid_array']) && in_array($question, $_SESSION['qid_array'])){
        $msg = "Sorry, Cheating is not allowed. You will now have to start over. Haha.";
        unset($_SESSION['answer_array']);
        unset($_SESSION['qid_array']);
        session_destroy();
        header("location: index.php?msg=$msg");
        exit();
    }
    if(isset($_SESSION['lastQuestion']) && $_SESSION['lastQuestion'] != $prev){
        $msg = "Sorry, Cheating is not allowed. You will now have to start over. Haha.";
        unset($_SESSION['answer_array']);
        unset($_SESSION['qid_array']);
        session_destroy();
        header("location: index.php?msg=$msg");
        exit();
    }
}
?>
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Quiz Page</title>
<script type="text/javascript">
function countDown(secs,elem) {
    var element = document.getElementById(elem);
    element.innerHTML = "You have "+secs+" seconds remaining.";
    if(secs < 1) {
        var xhr = new XMLHttpRequest();
        var url = "userAnswers.php";
            var vars = "checkbox=0"+"&qid="+<?php echo $question; ?>;
            xhr.open("POST", url, true);
            xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
            xhr.onreadystatechange = function() {
        if(xhr.readyState == 4 && xhr.status == 200) {
            alert("You did not answer the question in the allotted time. It will be marked as incorrect.");
            clearTimeout(timer);
    }
}
xhr.send(vars);
        document.getElementById('counter_status').innerHTML = "";
        document.getElementById('btnSpan').innerHTML = '<h2>Times Up!</h2>';
        document.getElementById('btnSpan').innerHTML += '<a href="quiz.php?question=<?php echo $next; ?>">Click here now</a>';

    }
    secs--;
    var timer = setTimeout('countDown('+secs+',"'+elem+'")',1000);
}
</script>
<script>
function getQuestion(){
    var hr = new XMLHttpRequest();
        hr.onreadystatechange = function(){
        if (hr.readyState==4 && hr.status==200){
            var response = hr.responseText.split("|");
            if(response[0] == "finished"){
                document.getElementById('status').innerHTML = response[1];
            }
            var nums = hr.responseText.split(",");
            document.getElementById('question').innerHTML = nums[0];
            document.getElementById('answers').innerHTML = nums[1];
            document.getElementById('answers').innerHTML += nums[2];
        }
    }
hr.open("GET", "questions.php?question=" + <?php echo $question; ?>, true);
  hr.send();
}
function x() {
        var rads = document.getElementsByName("rads");
        for ( var i = 0; i < rads.length; i++ ) {
        if ( rads[i].checked ){
        var val = rads[i].value;
        return val;
        }
    }
}
function post_answer(){
    var p = new XMLHttpRequest();
            var id = document.getElementById('qid').value;
            var url = "userAnswers.php";
            var vars = "qid="+id+"&checkbox="+x();
            p.open("POST", url, true);
            p.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
            p.onreadystatechange = function() {
        if(p.readyState == 4 && p.status == 200) {
            document.getElementById("status").innerHTML = '';
            alert("Thanks, Your answer was submitted"+ p.responseText);
            var url = 'quiz.php?question=<?php echo $next; ?>';
            window.location = url;
    }
}
p.send(vars);
document.getElementById("status").innerHTML = "processing...";

}
</script>
<script>
window.oncontextmenu = function(){
    return false;
}
</script>
</head>

<body onLoad="getQuestion()">
<div id="status">
<div id="counter_status"></div>
<div id="question"></div>
<div id="answers"></div>
<div id="status">
<div id="counter_status"></div>
<div id="question"></div>
<div id="answers"></div>
<h1>PONG</h1>
</div>
<script type="text/javascript">countDown(20,"counter_status");</script>
</body>
</html>

Answer 1

SELECT * FROM questions WHERE id='$question'

似乎您一次只选择一个问题，因此无需随机排序。

如果要选择随机问题，查询可能应如下所示：

SELECT * FROM questions WHERE 1=1 order by RAND() LIMIT 1

...但这需要重写一些相关代码：例如，每次都不需要强制question获取参数。

无法在mysql中随机化问题行

1 个答案: