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php - 谷歌饼图有问题从数据库中获取数据

问题描述

<?php
include('classes/DB.php');
$male = DB::query('SELECT COUNT(*) AS MTOTAL FROM users WHERE gender=\'male\';');
$female = DB::query('SELECT COUNT(*) AS FTOTAL FROM users WHERE gender=\'female\';');
?>

<html>
<head>
 <script type="text/javascript" src="https://www.gstatic.com/charts/loader.js"></script>
 <script type="text/javascript">
        google.charts.load('current', {'packages': ['corechart']});
        google.charts.setOnLoadCallback(drawChart);
        function drawChart() {
            var data = google.visualization.arrayToDataTable([
            ['Task', 'Number of Male and Female visitors'],
            ['Male', <?php while ($s = $male->fetch()) {echo $s ['count(*)'];}?>],
            ['Female', <?php while ($s = $female->fetch()) {echo $s ['count(*)'];}?>],
            ]);
            var chart = new google.visualization.PieChart(document.getElementById('piechart'))
            chart.draw(data, options);} </script>
</head>
<body>
<div id="piechart" style="width: 900px; height: 500px;"></div>
</body>
</html>

我想知道为什么我得到空数据。当我调用 echo json_encode($male) 和 json_encode($female) 时，我有真正的价值观。在这种情况下，我的数据库中有一个男性用户和三个女性用户，所以我看到输出为 [{"MTOTAL":"1","0":"1"}] [{"FTOTAL":"3"," 0":"3"}]。我想知道为什么我不能在脚本中获取这些值。

标签： phpmysqlchartsgoogle-visualization

解决方案

AS在您的查询中，您使用关键字 命名计数结果列...

SELECT COUNT(*) AS MTOTAL
SELECT COUNT(*) AS FTOTAL

使用名称来引用记录集中的列...

用这个... 

$s ['MTOTAL']
$s ['FTOTAL']

代替... 

$s ['count(*)']

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