title: Adding temporary column to table inside PLSQL
body: <p>The idea is that I have one column <code>Amount</code> which holds both negative and positive numbers. I would like to calculate <code>Balance</code> for each row that will have the the previous amount plus the value inside <code>Amount</code> for example</p>
  
  <pre><code>| Amount |   | Balance | 
  +--------+   |---------+
  |   +5   |   |     5   | -- Initial balance should be 0
  |   +100 |   |   105   |
  |   -10  |   |    95   |
  </code></pre>
  
  <p>What I would like to ask is what should be the method or the algorithm used to calculate <code>Balance</code>? </p>