问题描述
试图用MySQL中的数据生成HighCharts。使用PHP和json_encode函数从MySQL解析数据。问题：图表中没有数据。这是我的javascript：
<！DOCTYPE HTML>
< html>
< head>
< meta http-equiv =Content-Typecontent =text / html; charset = utf-8>
< title> Highcharts示例< / title>
< script type =text / javascriptsrc =https://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js><<< ; /脚本>
< 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 =containerstyle =max-width：500px; height：400px; margin：0 auto>< / div>
< / body>
< / html>
这是我的json.php：
<？php
$ host =localhost：3306;
$ user =removed;
$ pass =removed;
$ dbname =removed;
$ connection = mysqli_connect（$ host，$ user，$ pass，$ dbname）;
$ query =选择温度，时间从vejr时间>'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）;
？>
这是json.php的输出：
[{temp：1.6，time：2016-04-25 08:14:23}，{temp：2.6，time： 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，时间：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}]
我试图做的是带时间的图表（fx 2016-04-25 08:14:23）在x轴上，以及在y轴上的值（fx 1.6）。
从这得到灵感：
另外，我知道我在x轴上的时间戳并不完美，很长（2016- 04-25 08:14:23），但这正是我的饲喂软件目前发送给我的MySQL。什么是完美的？
亲切的问候
问题是造成3个原因。
- 值应该被命名为x和y，而不是自定义字段
- y值应该是数字，而不是像你这样的字符串（使用json_encode中的JSON_NUMERIC_CHECK标志）
- x值应该是时间戳（以毫秒为单位的时间）。在PHP中，您可以使用strtotime（）函数
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
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
这篇关于HighCharts和PHP json_encode。来自MySQL的数据。没有数据在图表上的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！