EventOptionRepository.php

См. документацию.

<?php
 
namespace Bitrix\Calendar\EventOption;
 
use Bitrix\Calendar\OpenEvents\Internals\OpenEventOptionTable;
 
final class EventOptionRepository
{
    public static function getIdsByCategoryId(int $categoryId): array
    {
        $query = OpenEventOptionTable::query();
        $query->where('CATEGORY_ID', $categoryId);
        $query->addSelect('ID');
        //TODO: possible too many items, memory usage?
        $eventOptions = $query->fetchAll();
 
        return array_column($eventOptions, 'ID');
    }
}