save and update the order of concatenation in the controller

I am looking to concatenate columns into a single , and be able to change the order that I can save it here is the schema of my table:

id	col1	col2	col3	separation	order	ref
	A	320	Audi	-	'col1','col2','col3'	A-320-Audi
	A	120	Audi	*	'col3','col2','col1'	Audi120A
	c	220	Aaudi	/	'col2','col3','col1'	220/audi/c

in my modification form the user can change the values ​​of the columns also the separation and the order but I also want to save the order that the user has chosen to use it in other pages

in my controller:

serials = Serial::findOrFail($id);
    $serials->update([
        'col1' => $request['col1'],
        'col2' => $request['col2'],
        'col3' => $request['col3'],
        'separation' => $request['separation'],
        'order' => $request['order'],
    ]);
DB::statement(DB::raw("UPDATE serials SET ref = CONCAT_WS(separation,order????) WHERE id = $id"));

problem 1:

how to register the chosen order correctly

in my input request of order someting like = 'col1','col2','col3'

problem 2 :

how to retrieve the value of the order and correctly execute the concatenation from the column order someting like :

DB::statement(DB::raw("UPDATE serials SET ref = CONCAT_WS(separation, ???'column:order'????) WHERE id = $id"));

via Chebli Mohamed