在Jquery Chart中循环以使其动态化

Im new in Js and Jquery and I have a curiosity about the Jquery Chart that is free to download and I want to make the data inside to be coming from the database to make it dynamic but somehow I find it difficult to loop it in.

here is my sample code, I used PHP to get the database and pass it on a JS variable

  <!DOCTYPE HTML>
   <html>

   <head>  
   <?php 
    $link = mysqli_connect("localhost","root","","raksquad_centralized") or      die("Error " . mysqli_error($link)); 
     if($link->connect_error){
          printf("Connect failed: %s
", $mysqli->connect_error);
          exit();
   }

    $query = "SELECT * FROM raksquad_centralized.grade";
    $result = $link->query($query); 

    $subject_id= array();
    $genAve = array();
    while($row = mysqli_fetch_array($result)){

      $subject_id[] = $row['subject_id'];
      $genAve[]= $row['gen_ave'];

  }

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


  window.onload = function () {
    var DataXAxis = <?php echo json_encode($subject_id); ?>; // X axis that corresponds to students
    var DataYAxis = <?php echo json_encode($genAve); ?>; // Y axis that corresponds to grades
    var chart = new CanvasJS.Chart("chartContainer",


    {
      title:{
        text: "Top Students"    
      },
      animationEnabled: true,
      axisY: {
        title: "Grades"
      },
        axisX: {
        title: "Students"
      },
      legend: {
        verticalAlign: "bottom",
        horizontalAlign: "center"
      },
      theme: "theme2",

      data: [

      {        
        type: "column",  
        showInLegend: true, 
        legendMarkerColor: "grey",
        legendText: "General Average",
        dataPoints:  [  
       //the area to loop with the value of DataXAxis, DataYAxis
        {y: 98,  label: "MT1234" },
        {y: 72,  label: "MT1236"} //corresponds to the barcharts 




        ]
      }   
      ]
    });

    chart.render();
  }
  </script>
  <script type="text/javascript" src="./canvasjs.min.js"></script>
</head>
  <body>
  <div id="chartContainer" style="height: 300px; width: 100%;">
    </div>
  </body>
</html>

appreciate for the help, useful for learning :)

I just use a php code to fetch the data, then json encode it.

On the script use json parse