Mysql count frequency

Question

I've checked similar questions but it didnt help in my precise question.

So, my table goes like this:

etc..

I need to count the frequency of ages:

age freq
30   2
36   3
52   2

How can I grab this freq? After this I will need to work with that data, so it might be necessary using array? Thanks!

function drawChart() {

      // Create the data table.

      var data = new google.visualization.DataTable();
      data.addColumn('string', 'age');
      data.addColumn('number', 'freq');

        <?php
            while($row = mysql_fetch_row($result)) 
            {
            $frequencies[$row[0]] = $frequencies[1];
            echo "data.addRow(['{$row[0]}', {$row[1]}]);";
            }

        ?>

The goal is build a chart

Nicholas Shanks · Accepted Answer · 2015-06-16T07:48:59.723

13

You need to group the rows by the common age, then count how many are in each group:

SELECT age, COUNT(*) AS freq FROM ages GROUP BY age

To then convert it into an array, do this in PHP:

$frequencies = array ();
$result = mysql_query('SELECT age, COUNT(*) AS freq FROM table GROUP BY age');
if($result === false) { handle error here... }
while($row = mysql_fetch_row($result)) {
    $frequencies[$row[0]] = $row[1];
}

You now have an associative array called $frequencies with the ages as keys and their frequency as values.

edited Jun 16 '15 at 07:48

answered Nov 15 '12 at 13:11

Nicholas Shanks

10,623
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Yes, Im using php and javascript – noneJavaScript Nov 15 '12 at 13:15
Im printing the frequencies array and it shows only the ages, what am i doing wrong? – noneJavaScript Nov 15 '12 at 13:29
@skdnewbie how are you printing the array? use `var_dump($frequencies)` to see the whole array as PHP sees it – Nicholas Shanks Nov 15 '12 at 13:30
hmm, array seems fine with var_dump, I might be using it wrong then. – noneJavaScript Nov 15 '12 at 13:38

score 2 · Answer 2 · answered Nov 15 '12 at 13:20

2

select age, name, count(*) freq from user_age group by age

Sqlfiddle : http://sqlfiddle.com/#!2/266d5/2

answered Nov 15 '12 at 13:20

Avin Varghese

4,340
1
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31

score 0 · Answer 3 · answered Nov 15 '12 at 13:11

0

select age, count(*) freq from mytable group by age

answered Nov 15 '12 at 13:11

n00b

4,341
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31
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score 0 · Answer 4 · answered Nov 15 '12 at 13:11

0

select age, count(id) as freq from table group by age

answered Nov 15 '12 at 13:11

Cedrun

457
2
8

Mysql count frequency

4 Answers4

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