Datediff from 2 colums : I am trying to get to know the days between 2 dates. But it will only return me errors. I tried searching it but non of the things really helped me, I am hoping you guys can help a boy out right here.

The error I get with this code: 

> Fatal error: Uncaught PDOException: SQLSTATE[42000]: Syntax error or
> access violation: 1582 Incorrect parameter count in the call to native
> function 'DATEDIFF' in
> C:\xampp\htdocs\Rent-a-Car\pages\medewerkers.php:197 Stack trace: #0
> C:\xampp\htdocs\Rent-a-Car\pages\medewerkers.php(197):
> PDO->query('SELECT DATEDIFF...') #1 {main} thrown in
> C:\xampp\htdocs\Rent-a-Car\pages\medewerkers.php on line 197

[my code to display it several times in the table][1]
[The database][2]

The sql codes that are used:

    $sql1 = "SELECT * FROM factuur 
    LEFT JOIN factuurregel ON factuur.Factuurnummer = factuurregel.Factuurnummer
    LEFT JOIN gebruiker ON factuur.Klantcode = gebruiker.Klantcode
    LEFT JOIN auto ON factuur.Kenteken = auto.Kenteken";
    $sql2 = "SELECT DATEDIFF (day, Begindatum, Einddatum) AS Tijd from factuurregel;";


  [1]: https://i.stack.imgur.com/5RIY4.png
  [2]: https://i.stack.imgur.com/5KqHz.png