private function buildCategoriesWhere($categories, $operator, $languageCode)
    {
        $structure = $this->structureManager->getStructure('excerpt');

        $sql2Where = [];
        if ($structure->hasProperty('categories')) {
            $property = new TranslatedProperty(
                $structure->getProperty('categories'),
                $languageCode,
                $this->languageNamespace,
                'excerpt'
            );
            foreach ($categories as $category) {
                $sql2Where[] = 'page.[' . $property->getName() . '] = ' . $category;
            }

            if (count($sql2Where) > 0) {
                return '(' . implode(' ' . strtoupper($operator) . ' ', $sql2Where) . ')';
            }
        }

        return '';
    }