title: Groupby and Sum from a datatable or dataview
body: <p>I have a datatable (filled from xls file) with different sort of fruits and legumes.</p>
  
  <p>I make a dataview from this datatable, and using RowFilter to only have the potatoes and tomatoes.</p>
  
  <p>Now, I try to make a groupby (with column 'Name') and making a sum from another column 'Quantity'.</p>
  
  <p>Actually :</p>
  
  <pre><code>Name    |  Quantity  | color
  tomatoe |     2      |  red
  tomatoe |     1      |  red
  potatoe |     5      |  yellow
  tomatoe |     1      |  red
  potatoe |     1      |  yellow
  </code></pre>
  
  <p>I would return a datatable or dataview like this :</p>
  
  <pre><code>Name    |  Quantity | color
  tomatoe |     4     |  red
  potatoe |     6     |  yellow
  </code></pre>
  
  <p>how can I do that ?</p>
  
  <p>Sorry if this is simple, but I'm noob with that.</p>