TSQL Challenge 65 - Solving the Running Total Problem
This challenge invites you to solve one of the most common calculation challenges seen in applications that deal with financial transactions.
This is not a very complicated challenge and there are different ways to solve this. The key here is to see some of the very efficient logical approaches to solve the Running Total problem.
http://beyondrelational.com/puzzles/challenges/99/solving-the-running-total-problem.aspx