Получить все родительские категории элемента инфоблока
SELECT parents.NAME FROM b_iblock_element el JOIN b_iblock_section sec ON (el.IBLOCK_SECTION_ID = sec.ID AND sec.IBLOCK_ID = 45) JOIN b_iblock_section parents ON (parents.LEFT_MARGIN <= sec.LEFT_MARGIN AND parents.RIGHT_MARGIN >= sec.RIGHT_MARGIN AND parents.IBLOCK_ID = 45) WHERE el.ID = 3633028;