title: Showing sum of multiple columns in datatables
body: <p>I am trying get the sum of multiple columns in my datatables. I am following the following link. <a href="https://datatables.net/examples/advanced_init/footer_callback.html" rel="nofollow noreferrer">https://datatables.net/examples/advanced_init/footer_callback.html</a>
  This datatables link explanation is really good in case of getting the sum of just one column, but my use case is to print multiple column sum (Even the sum of all the string values, for example all the users). </p>
  
  <p>I would appreciate any help. </p>