-----zadanie 2.0
SELECT SalesPersonID AS pracId , LastName + ',' + FirstName AS 'Nazwisko , Imię' , AVG(SubTotal) AS 'Średnia psrzedaż' ,
ROW_NUMBER() OVER (ORDER BY AVG(SubTotal) DESC) AS Ranking,
CASE (NTILE(2) OVER(ORDER BY AVG(SubTotal) DESC)) WHEN 1 THEN 'Wyróżniony'
WHEN 2 THEN 'Do weryfikacji' END AS 'Grupa'
FROM AdventureWorks.Sales.SalesOrderHeader
JOIN AdventureWorks.Person.Person
ON SalesPersonID = BusinessEntityID
GROUP BY SalesPersonID, LastName , FirstName
ORDER BY 3 DESC,2,1;