title: Invalid data table format: must have at least 2 columns
body: <p>I have a JSON string something like:</p>
  
  <pre><code>[
     {
        "Year":2018,
        "Ov":1000,
        "PD":2000,
        "OL":3000
     },
     {
        "Year":2017,
        "Ov":4000,
        "PD":5000,
        "OL":6000
     },
     {
        "Year":2012,
        "Ov":600,
        "PD":400,
        "OL":200
     },
     {
        "Year":2013,
        "Ov":700,
        "PD":500,
        "OL":200
     },
     {
        "Year":2014,
        "Ov":700,
        "PD":400,
        "OL":300
     },
     {
        "Year":2015,
        "Ov":700,
        "PD":300,
        "OL":400
     },
     {
        "Year":2016,
        "Ov":500,
        "PD":300,
        "OL":200
     },
     {
        "Year":2017,
        "Ov":4000,
        "PD":5000,
        "OL":6000
     },
     {
        "Year":2018,
        "Ov":1000,
        "PD":2000,
        "OL":3000
     }
  ]
  </code></pre>
  
  <p>My Html Code:</p>
  
  <pre><code>google.charts.load('current', {'packages':['bar']});
        google.charts.setOnLoadCallback(drawChart);
        var array = @Html.Raw(Json.Encode(Proj.Dash.JsonString));
       alert("JSON.stringify " + array);
  
       var dataArr = array.data;
  
      function drawChart() {
          var dataArray = [['Year', 'Ov', 'PD', 'OL']];
  
          for (var i in dataArr) {
              dataArray.push([dataArr[i].Year,dataArr[i].Ov,dataArr[i].PD,dataArr[i].OL]);
          }
          alert(dataArray.length);
  
            var data = google.visualization.arrayToDataTable([dataArray
  
  
          ]);
  
          var options = {
              chart: {
                  title: '',
                  subtitle: '',
              },
              bars: 'vertical',
              vAxis: { format: 'decimal' },
              height: 500,
              colors: ['#333333', '#3490e9', '#ff5a00'],
              legend: {
                  position: 'none'
              }
  
  
  
  
          };
  
          var chart = new google.charts.Bar(document.getElementById('columnchart_material'));
          chart.draw(data, google.charts.Bar.convertOptions(options));
        }
  </code></pre>
  
  <p>When I run the code it returns a null with this error:</p>
  
  <blockquote>
    <p>Invalid data table format: must have at least 2 columns.</p>
  </blockquote>
  
  <p>What do I missed up?</p>
  
  <p>Any suggestion is much appreciated.</p>