title: Removing Duplicated Substrings
body: <p>I understand that the following question may not be best practice.</p>
  
  <p>I have a table that has the following structure, the keyword column and title column concat into the mashup column.</p>
  
  <pre>
  +------------+------------+-----------------------+
  | Keyword    | Title      | Mashup                |
  +------------+------------+-----------------------+
  | Green      | Green      | Green Green           |
  | Green      | Watermelon | Green Watermelon      |
  | Watermelon | Watermelon | Watermelon Watermelon |
  +------------+------------+-----------------------+
  </pre>
  
  <p>I would like to know if there is a way of "deduping" the string. So my table will look more like the below:</p>
  
  <pre>
  +------------+------------+-----------------------+
  | Keyword    | Title      | Mashup                |
  +------------+------------+-----------------------+
  | Green      | Green      | Green                 |
  | Green      | Watermelon | Green Watermelon      |
  | Watermelon | Watermelon | Watermelon            |
  +------------+------------+-----------------------+
  </pre>
  
  <p>Is this possible? I can't seem to find a solution. Thanks!</p>
  
  <p>EDIT:</p>
  
  <pre>
  +------------+------------+-------------+-----------------------------+
  | Keyword    | Title      | Another     | Mashup                      |
  +------------+------------+-------------+-----------------------------+
  | Green      | Green      | Pink        | Green Green Pink            |
  | Green      | Watermelon | Yellow      | Green Watermelon Yellow     |
  | Watermelon | Watermelon | Black       | Watermelon Watermelon Black |
  +------------+------------+-------------+-----------------------------+
  </pre>