title: SQL needed: sum over values by month
body: <p>i have  an table   with values like this:</p>
  
  <pre><code>count1   count2  count3  month
  12        1       4       01/12/2011
  6         5       4       23/12/2011
  14        6       9       11/06/2011
  8         5       4       19/06/2011
  </code></pre>
  
  <p>How do I get the following results?</p>
  
  <pre><code>count1   count2  count3  month
  18        6       8       12
  22        11      13      06
  </code></pre>