title: DateTime group by date or hours
body: <p>01.02.2010 0:00:00 -> 01.02.2010 anytime</p>
  
  <p>01.02.2010 0:00:00 -> 01.02.2010 0:any minutes and seconds</p>
  
  <p>so here is my date :</p>
  
  <pre><code> DateTime x;
  </code></pre>
  
  <p>it's 
  01.02.2010 0:00:00
  as a string</p>
  
  <pre><code> x.Date.ToString()
  </code></pre>
  
  <p>here I compare date </p>
  
  <pre><code>DatarowsForOneDay = dt.Select("DailyRecTime= '" + x.ToString() + "'");
  </code></pre>
  
  <p>So how can I group by date + Hours without care about minutes and seconds.</p>