title: How to merge rows in a DataTable when data in multiple columns match?
body: <p>I am trying to figure out a good way to merge rows in a DataTable when column1, column2, column3, column4 match. Does anyone have pointers or ideas of how this can be accomplished in VB.NET and/or C#? </p>
  
  <pre><code>DataTable with duplicate rows to merge 
  -------------------------------------------------------------
  | Column1 | Column2 | Column3 | Column4 | Column5 | Column6 |
  -------------------------------------------------------------
  | 123456  | 6       | 54      | 5       | 0.00    | 36.78   |
  | 123456  | 6       | 54      | 5       | 21.00   | 0.00    |
  | 123456  | 6       | 54      | 8       | 0.00    | 102.09  |
  | 123456  | 6       | 54      | 8       | 6.50    | 0.00    |
  
  
  Final DataTable with merged rows 
  -------------------------------------------------------------
  | Column1 | Column2 | Column3 | Column4 | Column5 | Column6 |
  -------------------------------------------------------------
  | 123456  | 6       | 54      | 5       | 21.00   | 36.78   |
  | 123456  | 6       | 54      | 8       | 6.50    | 102.09  |
  </code></pre>