title: DATEDIFF function displayed error output in sqlserver
body: <p>i tried the code in mysql it is working well</p>
  
  <pre><code> select car_id,cust_id,due,DATEDIFF(NOW(),due) as elap from rental where car_id = '1'
  </code></pre>
  
  <p>issue date 2019-10-16  return date 2019-10-17
  have to calucalated elap result displayed in -1 it is working well.</p>
  
  <p>if i tried in sqlserver it produced wrong output </p>
  
  <pre><code>select cat_id,cust_id,date,due,DATEDIFF(dd,GETDATE(),due) as elap from rental where cat_id = '1'
  </code></pre>
  
  <p>have to calucalated elap result displayed in 1.wrong output  right on is -1 i don't know what is the error on sqlserver code </p>