fetch students from user table who not wrote specific exam(where comdtion) in exam table to get the absent list

check this part in the documentation

https://laravel.com/docs/7.x/eloquent-relationships#querying-relationship-absence

@tray2 thank you for your response let me try and inform you please

Look here, you can see that whereNotExists work with subquery.

Next thing whereHaswork with relationship as you can see here.

So does your User model relationship studentuser?

@tray2 @michaloravec thank you so much guys for your response.

i did like this and i got the solution.. whether this is right??

   $absentees = User::where('user_type','student')->doesntHave('studentuser', 'and', function($query) use ($request){
            $query->where('assessment_id', $request->assessment_id);
        })->orderBy('id','asc')->get();

fetch records from user table where user_type= student and check those students have records in 'studentuser' model for the assessment_id=$request->assessment_id

i have my relation like this User Model

  public function userprofile()
    {
        return $this->morphTo();
    }

    public function studentuser()
    {
        return $this->hasMany('App\StudentExamMain', 'student_id');
    }

My studentExamMain model

 public function user()
    {
        return $this->belongsTo('App\User', 'student_id');
    }

  public function assessmentmaindetails()
    {
        return $this->belongsTo('App\AssessmentCreationMain','assessment_id');
    }

But this query gives correct result. and my doubt is, i need to write a query for polymorphic relation.

$students=User::where('user_type','student')->WhereHas('userprofile', function ($query) use ($request) {
                $query->where([//      
         ['class_id',  $request->class_id],
         ['section',   $request->section_id],
     ]);
        })->doesntHave('studentuser', 'and', function($query) use ($request){
            $query->where('assessment_id', $request->assessment_id);
        })->orderBy('id','asc')->get();

for polymorphic i used like this and it showed error

Please use whereHasMorph() for MorphTo relationships.

so i changed WhereHas to WhereHasMorph but still showed error

Instantiation of 'Closure' is not allowed

what my expectation is to fetch records from user table where user_type='student' and check those student belongs to this class, this section in userprofile model and then check in studentuser model those students records are there or not for specific assessment_id

My user model

public function userprofile()
    {
        return $this->morphTo();
    }

    public function studentuser()
    {
        return $this->hasMany('App\StudentExamMain', 'student_id');
    }

My StudentRegistration model

 public function user()
    {
        return $this->morphOne('App\User', 'userprofile');
    }

any help please???

@abdulbazith Please read this whole part of documentation, because you mix it and everytime in wrong way.

Documentation: https://laravel.com/docs/7.x/eloquent-relationships

$students = User::where('user_type','student')->whereHasMorph('userprofile', 'App\User', function ($query) use ($request) {
    $query->where('class_id', $request->class_id)->where('section', $request->section_id);
})->whereDoesntHave('studentuser', function($query) use ($request) {
    $query->where('assessment_id', $request->assessment_id);
})->orderBy('id', 'asc')->get();

Also your naming of relationships is very confusing.

@michaloravec thank you soo much. and sorry for delay. the given code worked perfectly..

thank you. if possible kindly answer my other threads please..