SELECT *,
       --primary_id,  Первого повавшегося значения в данном случае по order by
       json_agg(email) over (PARTITION BY phone) as count_phone,
       count(phone) over (PARTITION BY phone) as count_phone
FROM client
         left join customer c on client.id = c.client_id
         left join "order" o on c.id = o.customer_id
where phone = '123456'
order by o.date_added