无法在Laravel数据透视表中获得关系

I want to build relations between three tables in laravel. Currently i have three models

Classroom,

public function subjects(){
return $this->belongstoMany('Subject','subject_section_classroom');
}

Section,
Subject

My Tables are

classrooms(id, name)
sections(id, name)
subjects(id, name)
subject_section_classroom( id, classroom_id, section_id, subject_id)

In my classroomsController I have

public function assignsubjects($class_id, $section_id){
        $classroom = Classroom::find($class_id);
        $section = Section::find($section_id); 
        $subjects = Subject::lists('name','id'); 
        $selected_subjects = $classroom->subjects()->where('section_id', '=', 1);
        $subjects = Subject::lists('name','id'); 
        return view('assignedit', compact('classroom','section','subjects', 'selected_subjects')); 
}

But I can't get the selected_subjects from above relation. And when I tried to get the sql of the above query (with ->toSQL()), I get

`"select * from `myschool_subjects` inner join `myschool_subject_section_classroom` on `myschool_subjects`.`id` = `myschool_subject_section_classroom`.`subject_id` where `myschool_subject_section_classroom`.`classroom_id` = ? and `section_id` = ?"`

I can't figure what I am doing wrong here. Please Help.

I think your problem is coming from php $selected_subjects = $classroom->subjects()->where('section_id', '=', 1);

Change it to: php $selected_subjects = $classroom->subjects()->where('section_id', '=', 1)->get();