title: Get row count in MySQLdb
body: <p>Is there a better way to get the row count than doing the following?</p>
  
  <pre><code>cursor.execute("SELECT DISTINCT(provider_id) FROM main_iteminstance")
  num_items = len(cursor.fetchall())
  </code></pre>
  
  <p>Is there a shorthand in <code>MySQLdb</code> for the above?</p>