How to select question from mysql tables randomly ?

[JosephHanh]

I am working on a quiz app

image 1 shows the index.php page
image 2 shows the first question
image 3 shows the second question
image 4 shows the third question
image 5 shows the result after completing the quiz
image 6 shows the database 'quizzer' and its tables
image 7 shows the 'questions' table
image 8 shows the 'choices' table

THIS LINK CONTAIN ALL THE CODE (and images) I HAVE DONE SO FAR

https://www.mediafire.com/folder/g5ao7f5q0fe6y/quiz

1.Now my question is how to select the question RANDOMLY from 'questions' table along with 'choices' (by adding code to the existing file or create a new one).

2.If user refresh/reload the page before starting ('Start Quiz') or click 'Take Again' after finishing the quiz, the question should appear randomly.

3.Basically I want to change the order of question appearing in the browser each time I refresh.

4.My work so far is mentioned above.........Please help me with this "RANDOM" problem !!

P.S - Will it be possible, by creating a random function in PHP which will check for repeat questions in a session and check for the 'id' of the question and if it is new display it on the page.

If so what should I do and if no then how to do?

[CroNiX]

You can just store the questions in an array and use shuffle() on the array. You can also use ORDER BY RAND() in your sql query, although I've read it's not as good in the past.

[Frank_b]

or this query:

SELECT * FROM pictures ORDER BY RAND() LIMIT 1;

[jcbones]

Don't use ORDER BY RAND(), if you want random from the database, check http://http://explainextended.com/2009/03/01/selecting-random-rows/ first.  After that, I like Cronix suggestion, using the session to store used question id's, so you can check against it for repeat questions.

[Barand]

Depends on how large the table is. That article is talking about millions of rows. With small tables the performance of ORDER BY RAND() should be acceptable

mysql> SELECT COUNT(*) FROM votes;
+----------+
| COUNT(*) |
+----------+
|   182685 |
+----------+
1 row in set (0.08 sec)

mysql> SELECT * FROM votes
    -> ORDER BY RAND()
    -> LIMIT 10;
+--------+-------+------+
| id     | votes | type |
+--------+-------+------+
| 153136 |   141 |   15 |
| 166164 |   646 |    5 |
|  58917 |   742 |   19 |
| 164668 |   273 |   13 |
|  87220 |   773 |    3 |
|  85013 |   600 |   18 |
| 137931 |   662 |    6 |
| 119082 |  1025 |    7 |
|  84811 |   480 |    9 |
| 111548 |   326 |    3 |
+--------+-------+------+
10 rows in set (0.18 sec)