title: How to copy multiple rows but change one field with mysql
body: <p>Say I have a table such as:</p>
  
  <pre><code>val cols cole
  1   1    3
  2   1    5
  4   1    9
  2   6    8
  3   1    9
  1   4    9
  2   9    9
  </code></pre>
  
  <p>I want a query that duplicates all rows where val=2 but change val to 5 for these new rows.</p>
  
  <p>Resulting in:</p>
  
  <pre><code>val cols cole
  1   1    3
  2   1    5
  4   1    9
  2   6    8
  3   1    9
  1   4    9
  2   9    9
  5   1    5
  5   6    8
  5   9    9
  </code></pre>