title: mssql 2008 datediff with minutes
body: <p>i am using this :</p>
  
  <pre><code>DECLARE @startdate datetime2 = '08:00:00.000';
  DECLARE @enddate datetime2 = '08:04:21.000'; 
  SELECT DATEDIFF(minute, @startdate, @enddate) as minute; 
  </code></pre>
  
  <p>and i get output 
  minute : 4</p>
  
  <p>but when i input below:</p>
  
  <pre><code>DECLARE @startdate datetime2 = '08:00:00.000';
  DECLARE @enddate datetime2 = '07:59:21.000'; 
  SELECT DATEDIFF(minute, @startdate, @enddate) as minute; 
  </code></pre>
  
  <p>then i get output : -1</p>
  
  <p>so i dont want output : -1  . it must be blank as output</p>
  
  <p>Thank you </p>