title: Update date in MySQL to contain leading zeros
body: <p>Let's say I have a column <code>col1</code> in table <code>tab1</code> that has following mixed format dates:</p>
  
  <pre><code>2015-03-03
  2015-02-03
  2017-3-6
  2015-03-04
  2017-11-6
  </code></pre>
  
  <p>What would be a good MySQL query to update this column to something more consistent, so all dates contain leading zeros</p>