Selecting random rows from database initially while preserving that order later

Question

I am building a quiz app, in which the student can login and can select the option of give exam. I want to show multiple choice questions to students randomly.

I stored all the questions in one table. For example, I stored 20 questions for a chemistry exam. Now I want to show 10 random questions to students. I don't want to select questions randomly every time when user refresh the page. Currently I am doing:

SELECT * from table-name order by rand() limit 5;

The problem is this query selects random rows every time the user refreshes the page. This is my code:

<?php
$query="SELECT * from question_bank order by rand() limit 10";
$result= mysqli_query($connection,$query);
confirm_query($result);

?>

<form action="result.php" name="form1" method="post" id="quiz">
<?php
while ($read_all_data = mysqli_fetch_assoc($result))
{ 
    $_SESSION['id']=1;

$id=$read_all_data['question_id'];
$a=$read_all_data['a'];
$b=$read_all_data['b'];
$c=$read_all_data['c'];
$d=$read_all_data['d'];
 echo $read_all_data['question']."</br>";
 echo "A:<input type ='radio' value ='a'  name='$id' >".$read_all_data['a']."</br>";
 echo "B:<input type ='radio' value ='b'  name='$id' >".$read_all_data['b']."</br>";
 echo "C:<input type ='radio' value ='c'  name='$id' >".$read_all_data['c']."</br>";
 echo "D:<input type ='radio' value ='d'  name='$id' >".$read_all_data['d']."</br>";

}

Answer 1

You'll want to hold an actual random number for each user then you can call

rand($usersrandomnumber) 

to generate your static random generator start point

the $usersrandomnumber acts as a starting seed

see the mysql documentation here: https://dev.mysql.com/doc/refman/5.0/en/mathematical-functions.html#function_rand

it will involve you storing the user's seed in a table somewhere, or cookie /local/server storage but will get you what you're after

Answer 2

Likely you'll want to hold the answers, too. That would be a suitable place to persist the ordering.

Table Answer
  Student_id
  Question_id
  Display_sequence
  Answer_value

Once you select questions insert them to this table. Each time you show a student's quiz check this table before creating a list.