Sorting questionnaire data using PHP and SQL

I have created a simple multiple choice questionnaire using HTML, PHP and SQL, which when submitted, adds numeric values to a table which each represent specific answers to each of the questions.

For example, I have four questions, and one submitted form may appear in my database cell as '0,1,3,1' (So answered the first option '0' for Question 1, and '1' for Question 2 etc;).

I'm now trying to output that data, and count how many people have selected which answer on each question.

How can I loop over that data in the table and get PHP to increment some kind of array each time so that I eventually ha开发者_如何学Pythonve a count of 'This many people answered X for Question X'.

I'm a little confused! Thanks in advanced.

/* EDIT */

My database layout is simple (possibly where I'm going wrong), it's simply:

Questionnaire ID | Results

1 --------------------0,1,3,2

(Couldn't get the table to layout well but hopefully that's clear)

As for what I have tried so far, not much as I couldn't think what to do.

I've got two for loops, one nested inside the other, that execute relative to the amount of questions I have, which create empty arrays for each question and answer.

Now I need to fill these arrays with counts of how many times each answer has been selected.

---

Why not do it in the original SQL, ie.

"select question, answer, count(answer)
group by question, answer"

This should then output a list of your questions, the answers that were chose, and how many times...

---

You should refactor your database to support these kind of queries.

But the following code may help in the meantime:

// 2 fake questionnaire copies. You will want to fetch these from your database
$test = array("1,2,3", "1,1,1");

// Sum up the answers
foreach ($test as $copy) {
    $answer_array = explode(",", $copy);
    foreach ($answer_array as $question => $answer) {
        $sum[$question][$answer]++;
    }
}

// Display the result
foreach ($sum as $question => $answer_sum) {
    echo "Question {$question}\n";
    foreach ($answer_sum as $answer => $sum) {
        echo "\t{$answer} answered {$sum} times\n";
    }
}