SQL dotaz, zkouska

select o.idOrder, count(*)
from "order" o
join customer c on o.idCustomer = c.idCustomer
join store s on s.idStore = o.idStore
join OrderItems oi on oi.idOrder = o.idOrder
where s.residence like 'B%' and c.fName = 'Martin' and c.lName = 'Krejčí' and birthday > '1980-01-01'
group by o.idOrder