title: Is there a way to merge multiple columns in react table
body: <p>I have a data array as: </p>
  
  <pre><code>data = [ {date: "16/05/2020", value: [ {column: "student", count: 10, value: "abcd" }, 
           {column: "teacher", count: 25, value: "pqrs" }] },
           {date: "17/05/2020", value: [ {column: "student", count: 19, value: "mno" }, 
           {column: "teacher", count: 7, value: "xyz" }] }
          ];
  </code></pre>
  
  <p>This is the column array:</p>
  
  <pre><code>columns = [{ Header: "Date", accessor: "date"}, 
             { Header: "Column", accessor: "column"},
             { Header: "Count", accessor: "count"},
             { Header: "Value", accessor: "value"}
             ]
  </code></pre>
  
  <p>I want to display the data as mentioned in the picture (<a href="https://i.stack.imgur.com/u6q2S.png" rel="nofollow noreferrer">table</a>) in React Table.</p>
  
  <p>Inside render(), I am doing this: </p>
  
  <pre><code>              &lt;ReactTable
                  data={data}
                  columns={columns}
                  minRows={0}
                  defaultPageSize={25}
                /&gt;
  </code></pre>
  
  <p>Kindly, help.</p>
  
  <p>Thanks in Advance!!</p>