title: how to categorize in mysql
body: <p>just think I have a table like shown below</p>
  
  <pre><code>**id**                           **product**
  
  2                                 chocolate
  1                                 chocolate    
  2                                 pepsi
  3                                 fanta
  2                                 pepsi
  4                                 chocolate
  5                                 chips
  3                                 pizza
  1                                 coke
  2                                 chips
  6                                 burger
  7                                 sprite
  0                                 pepsi
  </code></pre>
  
  <p>and want to arrange the above table in the manner shown below using only mysql  </p>
  
  <pre><code>**id**                   **product**
  0                          pepsi
  1                          chocolate, coke
  2                          chocolate,fanta,chips      
  3                          fanta,pizza
  4                          chocolate
  5                          chips
  6                          burger
  7                          sprite
  </code></pre>
  
  <p>how do I do it?</p>