title: Aggregating DataTable Without LINQ
body: <p>I want to aggregate a datatables rows based on some distinct values. I have to use Select and Compute methods or other non-linq approaches. 
  My question is: how can I aggregate (sum, count, min and ...) and grouping fields, and get results just like the sql server tables. Consider I have a table with four columns a, b, c, d. When I want to aggregate 'a' based on 'b, I can write:</p>
  
  <pre><code>Select sum(a) as 'a', b
  from myTable
  group by b
  </code></pre>
  
  <p>And the sql sever make a table with two columns, 'a' and 'b', so how can i do this in C# and using <code>DataTables</code>?
  I saw the examples of <code>DataTable.Compute()</code> in MSDN and the other related sources for aggregating and grouping the data in a datatable, but it return just an object value and it doesn't useful for grouping rows in datatable. in my problem, the user deiced to using of <code>sum</code>, <code>min</code>, <code>max</code>, or ... at run time, and  I trying to find a solution  for creating some dynamic queries.</p>