title: How to GROUP and choose lowest value in SQL
body: <p>I have table consisting of these fields:</p>
  
  <pre><code> id  |   date_from  | date_to      |   price
   --------------------------------------------
   CK1     22-12-2012   29-12-2012       800
   CK1     22-12-2012   29-12-2012       1200
   CK2     22-12-2012   29-12-2012       1400
   CK2     22-12-2012   29-12-2012       1800
   CK2     22-12-2012   29-12-2012       2200
  </code></pre>
  
  <p>How do I create SQL select that groups results by ID, DATE_FROM, DATE_TO and picks lowest value from price.</p>
  
  <p>So result would be</p>
  
  <pre><code> CK1     22-12-2012   29-12-2012       800
   CK2     22-12-2012   29-12-2012       1400
  </code></pre>