Select is not working in the hasMany Relationship

I have surveys and survey_votes table. the table structure is like

Table: surveys

• id
• title
• ... other fields

Table: survey_votes

• id
• ... other fields
• survey_id
• mark ( Number of votes )

and the relationship between these 2 tables is like.

class Survey extends Model
{
    public function votes() {
        return $this->hasMany(SurveyVote::class);
    }
}


class SurveyVote extends Model
{
    public function survey() {
        return $this->belongsTo(Survey::class);
    }
}

Now I fetching surveys with survey votes using with(). but getting empty results.

$surveys = Survey::with(['votes' => function ( $query ) {
    $query->select(\DB::raw('SUM(mark) total_votes'))->groupBy('survey_id');
}])->get();

and the strange thing is when I remove this $query->select() then it's working well. I have referred to all the links regarding this issue, but not work.

Note: I am using Laravel v5.8

Your suggestion is valuable for me, Thanks in Advance

via Chebli Mohamed