Group Totals - How To Sum Up Columns?

[GoogleCodeExporter]

What steps will reproduce the problem?
1. N/A

What is the expected output? What do you see instead?
I am trying to use the fnOnGroupCompleted: function( oGroup ) {} to calculate 
the totals for specific columns in the grouped rows. Can anyone give me a hint 
as to how I'd use oGroup to extract the values to be summed?

What version of the product are you using? On what operating system?
1.2.9

Please provide any additional information below.

Original issue reported on code.google.com by msp5...@gmail.com on 19 Dec 2013 at 8:11

[GoogleCodeExporter]

Hi, 
in the row we have group header. I would like to see the total of values 
present in specific columns. eg.

column1 column2 column3 column4
abc      2       xx      3
abc      1       ed      2

I want the grouped row as

abc      3               5

Please let me know if it is possible or not.

Original comment by virender...@gmail.com on 10 Sep 2014 at 1:59