fairlimitselector.php

<?php
namespace Bitrix\Iblock\ORM;
 
use Bitrix\Main\ORM\Fields\ExpressionField;
use Bitrix\Main\ORM\Objectify\Collection;
use Bitrix\Main\ORM\Objectify\EntityObject;
 
class FairLimitSelector
{
    public static function fetchCollection($query)
    {
        $select = $query->getSelect();
 
        $query->setSelect([new ExpressionField('DISTINCT_ID', 'DISTINCT %s', 'ID')]);
        $query->addGroup('ID');
 
        // get elements data
        $ids = [];
 
        foreach ($query->exec()->fetchAll() as $row)
        {
            $ids[] = $row['DISTINCT_ID'];
        }
 
        $dataClass = $query->getEntity()->getDataClass();
        $elements = $dataClass::createCollection();
 
        if (!empty($ids))
        {
 
            $query = $dataClass::query();
 
            $query->setSelect($select);
 
            $query->whereIn('ID', $ids);
 
            $resultElements = [];
 
            foreach ($query->fetchCollection() as $elementObject)
            {
                $resultElements[$elementObject->getId()] = $elementObject;
            }
 
            // original sort
            foreach ($ids as $id)
            {
                $elements->sysAddActual($resultElements[$id]);
            }
        }
 
        return $elements;
    }
}