title: How to add values of the same item in a column?
body: <p>I have the following columns in a table:</p>
  
  <ol>
  <li>Product Name</li>
  <li>Quantity</li>
  <li>Description</li>
  </ol>
  
  <p>I want to add the quantities of the product if the name of the product is same. For example if I have product with the same name twice, I want the total quantities of the products to be added and get a result.</p>
  
  <p>This is the table and I want to add the quantities of the same item:</p>
  
  <pre><code>Name            Quantity   Description
  Pen              3 
  Pencil           2
  Pen              6
  Eraser           7
  Eraser           6
  </code></pre>
  
  <p>For exmaple:</p>
  
  <ul>
  <li>I have pen twice and so want to add (3+6) and the display the total as 9, and ...</li>
  <li>I have eraser twice (7+6), so the total should be 13.</li>
  </ul>