title: How to get running sum of a column in sql server
body: <p>Hi I have a column with name Qty from table Bills
  i want a column that show the running sum of Qty column like this :</p>
  
  <pre><code>Qty   Run_Sum
  1      1
  2      3
  3      6
  4      10
  5      15
  </code></pre>
  
  <p>Suggest me some appropriate method to make running some thankx</p>