SELECT
    *
FROM TableA
LEFT JOIN TableB
    ON TableB.customer_id = TableA.customer_id
ORDER BY COALESCE(TableB.payDate, '1900-01-01') DESC

select customer.customer_id, customer.first_name, customer.last_name,
  max(payment.payment_date)
from customer
  left outer join payment on payment.customer_id = customer.customer_id
group by customer.customer_id, customer.first_name, customer.last_name
order by max(payment.payment_date) desc