Laravel打印sql

$link_popular_record_false = Student::whereNotIn('id',$temp_link_popular)
                    ->whereIn('id',$rand_arr)
                    ->limit($limit-$link_count)
                    ->get();

//打印写法故意写错select
$link_popular_record_false = Student::whereNotIn('id',$temp_link_popular)
                    ->select('asdasd')
                    ->whereIn('id',$rand_arr)
                    ->limit($limit-$link_count)
                    ->get();