HighCharts and PHP json_encode. Data from MySQL. No data on chart

Question

Trying to produce HighCharts with data from MySQL. Parsing data from MySQL using PHP and the json_encode function. Problem: No data on chart.

This is my javascript:

<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Highcharts Example</title>

<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"></script>
<style type="text/css">

</style>
<script type="text/javascript">

$(document).ready(function() {

    var options = {
        chart: {
            renderTo: 'container',
            type: 'spline'
        },
        series: [{}]
    };

    $.getJSON('json.php', function(data) {
        options.series[0].data = data;
        var chart = new Highcharts.Chart(options);
    });

});

</script>

<script src="https://code.highcharts.com/highcharts.js"></script>
<script src="https://code.highcharts.com/modules/exporting.js"></script>

</head>
<body>

<div id="container" style="max-width: 500px; height: 400px; margin: 0 auto"></div>

</body>
</html>

This is my json.php:

<?php

$host = "localhost:3306";
$user = "removed";
$pass = "removed";
$dbname = "removed";

$connection = mysqli_connect($host, $user, $pass, $dbname); 

$query = "SELECT temp, time from vejr where time > '2016-04-25 06:14:23'";

$result = mysqli_query($connection, $query);

$emparray = array();
    while($row =mysqli_fetch_assoc($result))
    {
        $emparray[] = $row;
    }
        echo json_encode($emparray);

?>

This is the output from the json.php:

[{"temp":"1.6","time":"2016-04-25 08:14:23"}, {"temp":"2.6","time":"2016-04-25 09:14:23"},{"temp":"3.6","time":"2016-04-25 10:14:23"},{"temp":"4.6","time":"2016-04-25 11:14:23"}, {"temp":"5.6","time":"2016-04-25 12:14:23"},{"temp":"6.6","time":"2016-04-25 13:14:23"},{"temp":"7.6","time":"2016-04-25 14:14:23"},{"temp":"8.6","time":"2016-04-25 15:14:23"}]

What I'm trying to do is a chart with time (fx 2016-04-25 08:14:23) on the x-axis, and the value (fx 1.6) on the y-axis.

Got inspiration from this: http://www.highcharts.com/docs/working-with-data/custom-preprocessing#3

And also, I know that my timestamp on the x-axis is not perfect, it is long (2016-04-25 08:14:23), but that is what my feeding-software currently is sending to my MySQL. What would be perfect?

Kind Regards

Sebastian Bochan · Accepted Answer · 2016-04-26 10:56:57Z

3

The issue is caused by 3 reasons.

Values should be named like x and y, not custom fields
The y value should be number, not string like you have (use the JSON_NUMERIC_CHECK flag in json_encode)
The x value, should be timestamp (time in miliseconds). In PHP you can use strtotime() function

edited Apr 26, 2016 at 10:56

answered Apr 26, 2016 at 10:51

Sebastian Bochan

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