json返回值未在php中绘制canvas.js条形图

我正在尝试使用canvas.js从json返回值中绘制条形图，在回调页面中获取值，但无法绘制图表

这是我的handler.php页面，其中生成了json值

<?php
include('connection.php');
if(isset($_POST)) {
$rep_date1=$_POST['date1'];
$date1=date("Y-m-d",strtotime($rep_date1));
$rep_date2=$_POST['date2'];
$date2=date("Y-m-d",strtotime($rep_date2));
$sql=mysql_query("SELECT * FROM infra.prob_report WHERE prob_rept_date BETWEEN '$date1' AND '$date2'");
$rows = array();
while($row = mysql_fetch_assoc($sql)) {     
    $nestedData=array(); 
    $nestedData[] = $row["rep_id"];
    $nestedData[] = $row["prob_rept_date"];
    $nestedData[] = $row["prob_equip_name"];
    $nestedData[] = $row["prob_rept_name"];
    $nestedData[] = $row["prob_desc"];
    $data[]= '<tr><td>'. $row["rep_id"]. '</td><td>'.    $row["prob_rept_date"]. '</td><td>'.$row["prob_equip_name"]. '</td><td>'. $row["prob_rept_name"]. '</td><td>'. $row["prob_desc"].'</td></tr>';
    $data_points = array("label" => $row['prob_equip_name'] , "y" => $row['rep_id']);

    }

    echo json_encode(array('data' => $data, 'dataPoints' => $data_points)); //json output populating data-grid and populating chart
}
?>

---

确切的问题是什么？@Matthijs图表没有打印它保持为空，我验证了返回值，它们对于打印图表是准确的
<script>
        $(document).ready(function() {

             $("#picker1").datepick();
             $("#picker2").datepick();
             $('#picker1').datepick('setDate', 'today');
             $('#picker2').datepick('setDate', 'today');

             $('#submit').click(function() {
                    var name=$("#name").val();
                    event.preventDefault();

            $.ajax({
                    type:"POST",
                    url: "new_prob_submit.php", 
                    data: { 
                        'date1': $('#picker1').val(), 
                        'date2': $('#picker2').val() 
                    },
                    dataType: "json",
                    success:function(result) {

                    $('#tbdy').html(result.data);

                    $.getJSON("handler.php", function (result) {
                    var chart = new CanvasJS.Chart("chartContainer", {
                        data: [
                                {
                                    dataPoints:  result.dataPoints 
                                }
                            ]
                        });
                            chart.render();
                        });
                    }
                });
            });


        });
   </script>