Edit in JSFiddle

$(document).ready(function() {
   var table = $('#example').DataTable({
      'ajax': 'https://gyrocode.github.io/files/jquery-datatables/arrays.json',
      'rowsGroup': [2]
   });   
});

<h3><a href="http://www.gyrocode.com/articles/jquery-datatables-rowspan-in-table-body-tbody/">jQuery DataTables - ROWSPAN in table body TBODY</a></h3>
<a href="http://www.gyrocode.com/articles/jquery-datatables-rowspan-in-table-body-tbody/">See full article on Gyrocode.com</a>
<hr><br>
    
<table id="example" class="display" cellspacing="0" width="100%">
   <thead>
      <tr>
         <th>Name</th>
         <th>Position</th>
         <th>Office</th>
         <th>Extn.</th>
         <th>Start date</th>
         <th>Salary</th>
      </tr>
   </thead>
   <tfoot>
      <tr>
         <th>Name</th>
         <th>Position</th>
         <th>Office</th>
         <th>Extn.</th>
         <th>Start date</th>
         <th>Salary</th>
      </tr>
   </tfoot>
</table>