title: Group by in DataTable Column sum
body: <p>In the following code for finding <code>sum of Rate colum</code>n in the <code>DataTable dt</code></p>
  
  <pre><code>dt.Compute("Sum(Convert(Rate, 'System.Int32'))");
  </code></pre>
  
  <p>In this is it possible to assign <code>group by clause like SQL</code> Inn order to get  Sum based on a value in another column of the same <code>dt</code>
  Fo eg:</p>
  
  <pre><code>----------------------------
  Rate | Group
  ----------------------------
  100  | A
  120  | B
  70   | A
  ----------------------------
  </code></pre>
  
  <p>I just wanna to get <code>Sum A=170</code> an <code>Sum B=120</code>.</p>