Do you want to get a table with
object sum1 = dTable.Compute("SUM(AutoID)", "group by Address");
It's wrong, Compute return a single value.
and the second parameter is the filter
so for select SUM(AutoId) from mytable where address = 'Ram Nagar, India'
object sum1 = dTable.Compute("SUM(AutoID)", "Address = 'Ram Nagar, India'");
you can use all SQL boolean command such as LIKE, <, >, <>