title: chart js Labels and Grouping labels
body: <p>Need a little schooling please.
  I have a working chart I  need to change it up a bit.
  My data has four fields omlPartgroup, xmonth, xyear and QTY
  I would like my chart to show each omlpartgroup and then the month and year in that group so I would have 12 bars for each partgroup and the labels would be the part group with sub groups of year and month. </p>
  
  <p>my code</p>
  
  <pre><code>window.jQuery(document).ready(function(){
  window.jQuery.ajax({
     url:"http://localhost/html5/data.php",
     method:"GET",
     success: function(data){
          console.log(data)
          var omlPartgroupid =[];
          var xyear =[];
          var xmonth =[];
          var QTY=[];
  
          for(var i in data){
              omlPartgroupid.push("PartGroup"+ data[i].omlPartgroupid);
              xyear.push(data[i].xyear);
              xmonth.push(data[i].xmonth);
              QTY.push(data[i].QTY);
              }
         var chartdata ={
             labels:xmonth,
             datasets :[
              {
             backgroundColor: 'rgba(200,200,200,0.75)',
             borderColor: 'rgba(200,200,200,0.75)',
             hoverBackground: 'rgba(200,200,200,1)',
             hoverBorderColor:  'rgba(200,200,200,1)',
             data:QTY
              }
                 ]
         };
         var ctx=$("#mycanvas");
         var barGraph =new Chart(ctx,{
             type: 'bar',
             data: chartdata
  
         });
     },
     error: function(data){
         console.log(data);
     }
  </code></pre>
  
  <p>});
  }); </p>
  
  <p>my data</p>
  
  <pre><code>[{"omlPartgroupid":"191  ","xmonth":"10","xyear":"2015","QTY":"52"},{"omlPartgroupid":"191  ","xmonth":"11","xyear":"2015","QTY":"145"},{"omlPartgroupid":"191  ","xmonth":"12","xyear":"2015","QTY":"122"},{"omlPartgroupid":"191  ","xmonth":"1","xyear":"2016","QTY":"348"},{"omlPartgroupid":"191  ","xmonth":"2","xyear":"2016","QTY":"460"},{"omlPartgroupid":"191  ","xmonth":"3","xyear":"2016","QTY":"187"},{"omlPartgroupid":"191  ","xmonth":"4","xyear":"2016","QTY":"109"},{"omlPartgroupid":"191  ","xmonth":"5","xyear":"2016","QTY":"234"},{"omlPartgroupid":"191  ","xmonth":"6","xyear":"2016","QTY":"166"},{"omlPartgroupid":"191  ","xmonth":"7","xyear":"2016","QTY":"186"},{"omlPartgroupid":"191  ","xmonth":"8","xyear":"2016","QTY":"250"},{"omlPartgroupid":"191  ","xmonth":"9","xyear":"2016","QTY":"1077"},{"omlPartgroupid":"191  ","xmonth":"10","xyear":"2016","QTY":"594"},{"omlPartgroupid":"193  ","xmonth":"10","xyear":"2015","QTY":"39"},{"omlPartgroupid":"193  ","xmonth":"11","xyear":"2015","QTY":"183"},{"omlPartgroupid":"193  ","xmonth":"12","xyear":"2015","QTY":"136"},{"omlPartgroupid":"193  ","xmonth":"1","xyear":"2016","QTY":"212"},{"omlPartgroupid":"193  ","xmonth":"2","xyear":"2016","QTY":"460"},{"omlPartgroupid":"193  ","xmonth":"3","xyear":"2016","QTY":"176"},{"omlPartgroupid":"193  ","xmonth":"4","xyear":"2016","QTY":"187"},{"omlPartgroupid":"193  ","xmonth":"5","xyear":"2016","QTY":"174"},{"omlPartgroupid":"193  ","xmonth":"6","xyear":"2016","QTY":"151"},{"omlPartgroupid":"193  ","xmonth":"7","xyear":"2016","QTY":"164"},{"omlPartgroupid":"193  ","xmonth":"8","xyear":"2016","QTY":"237"},{"omlPartgroupid":"193  ","xmonth":"9","xyear":"2016","QTY":"798"},{"omlPartgroupid":"193  ","xmonth":"10","xyear":"2016","QTY":"662"},{"omlPartgroupid":"195  ","xmonth":"10","xyear":"2015","QTY":"9"},{"omlPartgroupid":"195  ","xmonth":"11","xyear":"2015","QTY":"38"},{"omlPartgroupid":"195  ","xmonth":"12","xyear":"2015","QTY":"35"},{"omlPartgroupid":"195  ","xmonth":"1","xyear":"2016","QTY":"68"},{"omlPartgroupid":"195  ","xmonth":"2","xyear":"2016","QTY":"161"},{"omlPartgroupid":"195  ","xmonth":"3","xyear":"2016","QTY":"73"},{"omlPartgroupid":"195  ","xmonth":"4","xyear":"2016","QTY":"69"},{"omlPartgroupid":"195  ","xmonth":"5","xyear":"2016","QTY":"56"},{"omlPartgroupid":"195  ","xmonth":"6","xyear":"2016","QTY":"55"},{"omlPartgroupid":"195  ","xmonth":"7","xyear":"2016","QTY":"50"},{"omlPartgroupid":"195  ","xmonth":"8","xyear":"2016","QTY":"114"},{"omlPartgroupid":"195  ","xmonth":"9","xyear":"2016","QTY":"1046"},{"omlPartgroupid":"195  ","xmonth":"10","xyear":"2016","QTY":"883"},{"omlPartgroupid":"197  ","xmonth":"10","xyear":"2015","QTY":"34"},{"omlPartgroupid":"197  ","xmonth":"11","xyear":"2015","QTY":"76"},{"omlPartgroupid":"197  ","xmonth":"12","xyear":"2015","QTY":"114"},{"omlPartgroupid":"197  ","xmonth":"1","xyear":"2016","QTY":"173"},{"omlPartgroupid":"197  ","xmonth":"2","xyear":"2016","QTY":"327"},{"omlPartgroupid":"197  ","xmonth":"3","xyear":"2016","QTY":"134"},{"omlPartgroupid":"197  ","xmonth":"4","xyear":"2016","QTY":"125"},{"omlPartgroupid":"197  ","xmonth":"5","xyear":"2016","QTY":"200"},{"omlPartgroupid":"197  ","xmonth":"6","xyear":"2016","QTY":"104"},{"omlPartgroupid":"197  ","xmonth":"7","xyear":"2016","QTY":"99"},{"omlPartgroupid":"197  ","xmonth":"8","xyear":"2016","QTY":"191"},{"omlPartgroupid":"197  ","xmonth":"9","xyear":"2016","QTY":"845"},{"omlPartgroupid":"197  ","xmonth":"10","xyear":"2016","QTY":"578"},{"omlPartgroupid":"199  ","xmonth":"10","xyear":"2015","QTY":"35"},{"omlPartgroupid":"199  ","xmonth":"11","xyear":"2015","QTY":"75"},{"omlPartgroupid":"199  ","xmonth":"12","xyear":"2015","QTY":"76"},{"omlPartgroupid":"199  ","xmonth":"1","xyear":"2016","QTY":"105"},{"omlPartgroupid":"199  ","xmonth":"2","xyear":"2016","QTY":"229"},{"omlPartgroupid":"199  ","xmonth":"3","xyear":"2016","QTY":"147"},{"omlPartgroupid":"199  ","xmonth":"4","xyear":"2016","QTY":"73"},{"omlPartgroupid":"199  ","xmonth":"5","xyear":"2016","QTY":"50"},{"omlPartgroupid":"199  ","xmonth":"6","xyear":"2016","QTY":"58"},{"omlPartgroupid":"199  ","xmonth":"7","xyear":"2016","QTY":"103"},{"omlPartgroupid":"199  ","xmonth":"8","xyear":"2016","QTY":"4230"},{"omlPartgroupid":"199  ","xmonth":"9","xyear":"2016","QTY":"2570"},{"omlPartgroupid":"199  ","xmonth":"10","xyear":"2016","QTY":"730"}]
  </code></pre>