get data from database

app/Http/Controllers/Controller.php

@@ -148,7 +148,7 @@ class Controller extends BaseController
     public function getDatabase(Request $request)
     {
         
-        $staff = Staff::where('api_token', '' )->where('roles_access','Installer')->get();
+        $staff = Staff::where('api_token', null )->where('roles_access','Installer')->get();
 
         return $staff;
     }