title: SQL server 2008, datediff returns wrong value
body: <p>I have two columns of Data type time. I'm using datediff to find the difference in hours.
  The problem is when I try to find the difference between 00:00:00 to 06:00:00, it returns -18.
  How can I fix it?
  note: I need to calculate more difference with this so I can't just divide it with -3</p>
  
  <pre><code>my function- (datediff(HOUR, startHour, endHour))*60
  </code></pre>
  
  <p>Thanks in advance      </p>