Explode string if not between ()

I am trying to explode

create a line with a comma: ,

but only if it is not between the brackets(...)

Here's some code to show what I mean:

$string = "K.VisueelNr,IFNULL(P.Partijnaam, 'Leeg gemeld') AS Partijnaam,R.Ras,M.Maat,DATE_FORMAT(KS.Timestamp, '%d-%c-%Y') AS Datum,H.Handelshuis,KS.Actie";

print_r(str_getcsv($string, '()'));

print_r(explode(",", $string));

      

        
        
        
      

    

The output will be:

Array
(
    [0] => K.VisueelNr,IFNULL
    [1] => P.Partijnaam, 'Leeg gemeld') AS Partijnaam,R.Ras,M.Maat,DATE_FORMAT
    [2] => KS.Timestamp, '%d-%c-%Y') AS Datum,H.Handelshuis,KS.Actie
)
Array
(
    [0] => K.VisueelNr
    [1] => IFNULL(P.Partijnaam
    [2] =>  'Leeg gemeld') AS Partijnaam
    [3] => R.Ras
    [4] => M.Maat
    [5] => DATE_FORMAT(KS.Timestamp
    [6] =>  '%d-%c-%Y') AS Datum
    [7] => H.Handelshuis
    [8] => KS.Actie
)

      

        
        
        
      

    

But I'm looking for an output like this:

Array
(
    [0] => K.VisueelNr
    [1] => IFNULL(P.Partijnaam, 'Leeg gemeld') AS Partijnaam
    [2] => R.Ras
    [3] => M.Maat
    [4] => DATE_FORMAT(KS.Timestamp, '%d-%c-%Y') AS Datum
    [5] => H.Handelshuis
    [6] => KS.Actie
)

      

        
        
        
      

    

Here's a PHP Sandbox script to play around

It might need to be done with preg_split , but I don't know what it looks like regex

then ...