谷歌图表组按秒计算

Question

为简单起见，我为问题jsfiddle制作了此图表。 我可以按秒或分钟或小时对这些条形图进行分组吗？ 新的分组条应该具有值2但不是1，即分组的条形它是总和 jsfiddle中的代码：

google.charts.load('current', {'packages':['bar']});
google.charts.setOnLoadCallback(drawChart);

function drawChart() {

  var data = new google.visualization.DataTable();
  data.addColumn('timeofday', 'Time of Day');
  data.addColumn('number', 'Emails Received');

  data.addRows([
    [[8,30,30],1],
    [[8,30,30],1],
    [[8,30,31],1],
    [[8,30,31],1],
    [[8,30,32],1],
    [[8,30,32],1],
    [[8,30,33],1],
    [[8,30,33],1],
    [[8,30,34],1],
    [[8,30,34],1],
  ]);

  var options = google.charts.Bar.convertOptions({
    title: 'Total Emails Received Throughout the Day',
    height: 450
  });

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

  chart.draw(data, options);
}