我的表（tb_ticket）哪像这样：
| 技术人员_1|技术员_2|
| - -|- -|
| 埃马|埃马|
| 汤姆|埃马|
| 丽莎|汤姆|
| 阿那|丽莎|
| 汤姆|汤姆|
我的问题是如何使它变成这样：
艾玛=3，汤姆=4，安娜=1，丽莎=2
我的查询

<script>
var ctx = document.getElementById("myChart").getContext('2d');
  var myChart = new Chart(ctx, {
         type: 'bar',
               data: {
                  labels: ["Ema", "Tom", "Ana", "Lisa"],
                  datasets: [{
                  label: 'Request by technician',
                  data: [  

                  <?php 
                  $technician_ema= mysqli_query($koneksi,"select * from tb_ticket where (technician_1','technician_2)='Ema'");
                  echo mysqli_num_rows($technician_ema);
                  ?>, 

                  <?php 
                  $technician_tom= mysqli_query($koneksi,"select * from tb_ticket where (technician_1','technician_2)='Tom'");
                  echo mysqli_num_rows($technician_tom);
                  ?>,

                  <?php 
                  $technician_ana= mysqli_query($koneksi,"select * from tb_ticket where (technician_1','technician_2)='Ana'");
                  echo mysqli_num_rows($technician_ana);
                  ?>, 
                  <?php 
                  $technician_lisa= mysqli_query($koneksi,"select * from tb_ticket where (technician_1','technician_2)='Lisa'");
                  echo mysqli_num_rows($technician_lisa);
                  ?>

                   ],
                   backgroundColor: [
                   '#1B4F72',
                   '#21618C',
                   '#2874A6',
                   '#2E86C1'
                    ],
                    }]
                    },
                   options: {
                       scales: {
                           xAxes: [{
                              ticks: {
                                autoSkip: false
                                }
                             }]
                            }
                           }
                        });
                 </script>

将列technician_1和technician_2中的技术人员总数合并到一个条形图中。
My chart like this