whereBetween doesnt exist and i cant apply paginate - laravel

Question

I've this method:
public function indexGuest($idAzienda, Request $request){
$companyId = $idAzienda;
$ddts = Ddt::where('company_id',$companyId);
$ddt_urls= Ddt_file_url::all();
if($request->start_date || $request->end_date){
$ddts->whereBetween('created_at',[new Carbon($request->start_date),new Carbon($request->end_date)]);
}
$ddts->paginate(10);
return view('guest.ddt-management')->with('ddts', $ddts)->with('ddt_urls',$ddt_urls)
->with('companyId',$companyId);
}
My start_date and end_date comes in strings like "yyyy-mm-dd".
I've tried to pass it straight to the query and like in the example like a carbon object with no hope!
After executing the query (now only the one without the wherebeeteween clause) i cant apply the method "paginate" to the collection, no error are raised but when i pass it to the view, the "link()" method not work and raise an error again.
where I wrong?
Laravel 5.4

Answer 1

Structure your wheres like this.
public function indexGuest($idAzienda, Request $request) {
[...]
$ddts = Ddt::where('company_id', $companyId)
->where(function($query) use ($request) {
if($s = $request->get("start_date") {
$s_date = Carbon::parse($s)->format("Y-m-d");
$query->whereDate("created_at", ">=", $s_date);
}
if($e = $request->get("end_date") {
$e_date = Carbon::parse($e)->format("Y-m-d");
$query->whereDate("created_at", "<=", $e_date);
}
})
->paginate(10);
[...]
}