Pour vous aider en cas de difficultés, voici le code SQL final de la session suivante. Vous pouvez également vous entrainer, en l'écrivant avec moi.

Exemple 1

SELECT C.CustomerID, C.PersonID

FROM Sales.Customer AS C

WHERE EXISTS ( SELECT 1

FROM Sales.SalesOrderHeader AS S

WHERE S.CustomerID = C.CustomerID AND S.TotalDue >= 1000

);

Exemple 2

SELECT P.ProductID, P.Name, P.ListPrice, PS.Name AS SubcategoryName FROM Production.Product AS P

JOIN Production.ProductSubcategory AS PS

ON P.ProductSubcategoryID = PS.ProductSubcategoryID

WHERE P.ListPrice > ( SELECT AVG(P2.ListPrice)

FROM Production.Product AS P2 WHERE P2.ProductSubcategoryID = P.ProductSubcategoryID

);

Exemple 3

SELECT C.CustomerID, C.personID, Sales.salesorderID, Sales.totaldue

FROM Sales.Customer AS C

INNER JOIN Sales.Salesorderheader AS Sales

ON C.CustomerID = Sales.CustomerID

WHERE EXISTS ( SELECT 1

FROM Sales.Salesorderheader AS O

WHERE O.CustomerID = C.CustomerID

AND O.TotalDue > ( SELECT AVG(O2.TotalDue)

FROM Sales.Salesorderheader AS O2

WHERE O2.CustomerID = C.CustomerID )

);

