title: MySQL: how to use COALESCE
body: <p>Say I have the following table:</p>
  
  <pre><code>TABLE: product
  ===============================================================================
  | product_id | language_id | name           | description                     |
  ===============================================================================
  | 1          | 1           | Widget 1       | Really nice widget. Buy it now! |
  -------------------------------------------------------------------------------
  | 1          | 2           | Lorem  1       |                                 |
  -------------------------------------------------------------------------------
  </code></pre>
  
  <p>How do I query this such that it tries to give me the <code>name</code> and <code>description</code> where <code>language_id</code> = 2, but fall back to <code>language_id</code> = 1 if the column contains a NULL?</p>
  
  <p>In the above example, I should get <code>Lorem 1</code> for <code>name</code> and <code>Really nice widget. Buy it now!</code> for <code>description</code>.</p>