how to select random rows from a table in sql of different categories given as input

Question

ex:subject type means g.k,english,maths etc... like that. my question is for preparing questionpapers by randomly selecting the questions of different questions

Can you please guide regarding this query....?

It's very unclear to me. Can't you just retrieve all questions and perform randomization on that? — Jeroen Vannevel, Jun 27 '13 at 11:44
It means that we will have a table which contains questions of all categories(eng,maths,science,social ...etc).we need to select questions from that table randomly ,which we will give input to that like , the result should contain questions that, from maths-3,science-6,g.k-5 — user2527874, Jun 27 '13 at 11:50
This is a very poorly articulated question. Reading through the comments, I think what you're trying to ask is "How can I randomly select x number of questions from each category?" — Strawberry, Jun 27 '13 at 12:12
Search up one of the million greatest-n-per-group questions here on SO and combine it with ORDER BY RAND(); — fancyPants, Jun 27 '13 at 12:31

score 1 · Answer 1 · edited Jun 27 '13 at 11:48

1

Maybe not the best solution but should work: use a SELECT Query selecting the top 10 or 20 rows from a query ordered by RAND

eg:

SELECT * FROM questions_table WHERE subject='maths' ORDER BY RAND() LIMIT 0, 10

edited Jun 27 '13 at 11:48

Sathish D

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answered Jun 27 '13 at 11:46

Matt.C

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some what better,but not only maths it should contain all the subjects in where condition – user2527874 Jun 27 '13 at 11:53
if you want it selected from ALL subjects, just remove the where clause, SELECT * FROM questions_table ORDER BY RAND() LIMIT 0, 10 – Matt.C Jun 27 '13 at 11:56
if you want multiple subjects but not all of them, extend the where clause SELECT * FROM questions_table WHERE subject='maths' OR subject='physics' ORDER BY RAND() LIMIT 0, 10 – Matt.C Jun 27 '13 at 11:58
but the result may not contain all the subjects – user2527874 Jun 27 '13 at 11:58
sir other than that no other option? – user2527874 Jun 28 '13 at 08:04

score 1 · Answer 2 · edited Jun 27 '13 at 12:30

1

$sub1=$_POST['sub1'];
$no1=$_POST['no1'];

$sub2=$_POST['sub2'];
$no2=$_POST['no2'];

(assuming you are getting these values from a form)

mysql_query=('SELECT question FROM question_bank WHERE subject="'.$subj1.'" ORDER BY RAND() LIMIT $no1;

UNION

SELECT question FROM question_bank WHERE subject="'.$subj2.'" ORDER BY RAND() LIMIT $no2;')

.... so on... for all the subjects

edited Jun 27 '13 at 12:30

fancyPants

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answered Jun 27 '13 at 12:27

kevinm

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thank you sir.another question after selecting 50 questions using above query ,we need to divide 50 questions into 5 sets means that each set must contain 10 ques(assume) – user2527874 Jun 27 '13 at 12:41

score 0 · Answer 3 · edited Jun 27 '13 at 12:31

0

If you want questions from all subjects you can use :

SELECT question FROM question_bank ORDER BY RAND() LIMIT 50;

here 50 is the maximum number of rows in the table upto which you want to search and select the questions.

Now, If you want a subject-wise selection, you can use

SELECT question FROM question_bank WHERE subject='GK' ORDER BY RAND() LIMIT 50;

edited Jun 27 '13 at 12:31

fancyPants

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answered Jun 27 '13 at 11:55

kevinm

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I think the first query in my answer should help, unless you need a fixed number of questions from each subject. – kevinm Jun 27 '13 at 11:57
yes,we will give fixed no. of questions for each subject – user2527874 Jun 27 '13 at 12:06
I think you will need the help of a programming language for this. – kevinm Jun 27 '13 at 12:26
can you help me with the code sir? – user2527874 Jun 27 '13 at 13:14

how to select random rows from a table in sql of different categories given as input

3 Answers3