title: MySQL, adding a string to all column values
body: <p>Have a MySQL database table with 2 columns:
  id, url</p>
  
  <p>The url column has values like 'http://www.example.com/'.</p>
  
  <p>I need to add a string like 'http://www.x.com?redirect=' to the beginning of all the column values - i.e. to change the values like this:
  <a href="http://www.example.com/" rel="nofollow">http://www.example.com/</a> ===> <a href="http://www.x.com?redirect=http://www.example.com/" rel="nofollow">http://www.x.com?redirect=http://www.example.com/</a></p>
  
  <p>Anyone has some clues to how I can do that?</p>
  
  <p>I have looked into using CONCAT(), but so far I haven't been able to make it work :(</p>
  
  <p>Thanks a lot for your help,
  Louisa</p>