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How to get a percentage of total when the query has a GROUP BY?（5个答案）
17小时前关门了。
我有一个饼图，它引用数组中的值。
我想把这些数组值显示为百分比。我该怎么做？
我用来生成此饼图的插件是chart.js
Javascript供参考：

success : function (data){
    console.log(data);

    var categoryname = ["Drain", "Building", "Pest", "Broken Utilities", 
    "Littering", "Leakage", "Lighting"];
    var category = [];
    var amount = [];

    for (var i in data) { 
        category.push(categoryname[data[i].Category]);
        amount.push (data[i].CaseNum);
    }
    var config = {
        type: 'pie',
        data: {
            datasets: [{
                data: amount,
                backgroundColor: [
                    "rgba(59, 89, 152, 1)",
                    "rgba(59, 89, 152, 1)",
                    "rgba(59, 89, 152, 1)",
                    "rgba(59, 89, 152, 1)",
                    "rgba(59, 89, 152, 1)",
                    "rgba(59, 89, 152, 1)",
                    "rgba(59, 89, 152, 1)"
                    ],
                label: 'Dataset 1'
            }],
                labels: category
        },
        options: {
            responsive: true
        }
    };
    var ctx = $("#mycanvas");       
    var graph = new Chart(ctx, config);
}

Php供参考：

$query = "SELECT categoryID as 'Category', COUNT(Case.categoryID) as 'CaseNum' 
FROM `Case` WHERE CaseTime BETWEEN DATE_SUB(now(), INTERVAL 6 MONTH) AND 
now() GROUP BY categoryID ORDER BY categoryID";

$result = $conn->query($query);

$data = array();
foreach ($result as $row) {
    $data[] = $row;
}

$conn->close();

print json_encode($data);

Piechart图像示例：