title: Alter a MySQL column to be AUTO_INCREMENT
body: <p>I’m trying to modify a table to make its primary key column <code>AUTO_INCREMENT</code> after the fact.  I have tried the following SQL, but got a syntax error notification.</p>
  
  <pre class="lang-sql prettyprint-override"><code>ALTER TABLE document
  ALTER COLUMN document_id AUTO_INCREMENT
  </code></pre>
  
  <p>Am I doing something wrong or is this not possible?</p>
  
  <pre>
  +--------------------+
  | VERSION()          |
  +--------------------+
  | 5.0.75-0ubuntu10.2 |
  +--------------------+
  </pre>