JS - GOOGLE CHART PHP MYSQL

<?php


require 'connect.php';

?>


<html>
  <head>
    <script type="text/javascript" src="https://www.gstatic.com/charts/loader.js"></script>

    <script type="text/javascript">
      google.charts.load('current', {'packages':['bar']});
      google.charts.setOnLoadCallback(drawChart);

      function drawChart() {
        var data = google.visualization.arrayToDataTable([

        ['mese','somma'],


          <?php


  $query = "SELECT DATE_FORMAT(timeof, '%m-%Y') AS mese, SUM(totsell-cost) AS somma FROM position WHERE DATE_FORMAT(timeof, '%m-%Y') GROUP BY mese";
  $exec = mysqli_query($conn,$query);
  while($row = mysqli_fetch_array($exec)){
  echo "['".$row['mese']."',".$row['somma']."],";
}


          ?>


            ]);


        var options = {

          title: '',

          colors: ['grey', '#618C5B', '#DB3D52', '#993333'],
          legend: {position: 'none'},
          width: 300,
          height: 200,

          bar: {groupWidth: '20px'},

          backgroundColor: 'transparent'


        };

        var chart = new google.charts.Bar(document.getElementById('columnchart_material'));

        chart.draw(data, google.charts.Bar.convertOptions(options));
      }
    </script>
  </head>
  <body>
    <div id="columnchart_material" style="width: 940px; height: 170px;"></div>
  </body>
</html>