title: How can i merge duplicate rows in SQL with an special condition
body: <p>i have a table with this structure</p>
  
  <pre><code>ID    Word         description
  -------------------------------
  1     book       a lot of paper
  2     book       a thing
  3     book       an amazing thing
  4     tv         television
  </code></pre>
  
  <p>i want to convert this table to: </p>
  
  <pre><code>ID    Word         description
  -------------------------------
  1     book       a lot of paper,a thing,an amazing thing
  2     tv         television
  </code></pre>
  
  <p>Note that :</p>
  
  <p>-The maximum number of duplication is six</p>
  
  <p>-I want to have a table without duplicate rows , i want to merge all duplicate rows to one row with all description values.</p>
  
  <p>Thanks for your helps...</p>