Удаляет несуществующие номера телефонов

DELETE b_crm_field_multi
FROM b_crm_contact
RIGHT OUTER JOIN b_crm_field_multi
ON b_crm_field_multi.element_id = b_crm_contact.id
WHERE b_crm_field_multi.entity_id = 'CONTACT' AND b_crm_contact.id IS NULL;