-- zad3 OK
SELECT	YEAR(OrderDate) Rok,
		MONTH(OrderDate) Miesiąc,
		DAY(OrderDate) Dzień,
		SUM(Sales.SalesOrderHeader.SubTotal) Kwota,
		Count(*) "Liczba zamówień"
FROM	Sales.SalesOrderHeader
GROUP BY ROLLUP(YEAR(OrderDate), MONTH(OrderDate), DAY(OrderDate))
HAVING YEAR(OrderDate) IS NOT NULL AND MONTH(OrderDate) IS NOT NULL AND DAY(OrderDate) IS NOT NULL
ORDER BY YEAR(OrderDate), MONTH(OrderDate), DAY(OrderDate)

-- zad4 OK
SELECT	SalesPersonID pracID,
		CustomerID klientID,
		ROUND(SUM(SubTotal),2) Suma
FROM	Sales.SalesOrderHeader
GROUP BY ROLLUP(SalesPersonID, CustomerID)
ORDER BY SalesPersonID, CustomerID, COUNT(SalesOrderID) DESC