13. SELECT * FROM Clients WHERE Entreprise='True'

14. SELECT NPro, Libelle, Prix FROM Produits WHERE Prix<10

15. SELECT COUNT(*) FROM Commandes

16. SELECT NClient, COUNT(*) FROM Commandes GROUP BY NClient

17. SELECT SUM(Quantite) FROM Details 
On obtient 3327 articles.

18. SELECT NProduit, AVG(Quantite) FROM Details 
   GROUP BY NProduit

19. SELECT DISTINCT NClient FROM Commandes ORDER BY NClient
\end{SQL}

20. SELECT NCli AS NClient FROM Clients
   EXCEPT
   SELECT NClient FROM Commandes
Il reste les clients 20, 31, 33, 41, 44, 45. 

21. SELECT * FROM Clients JOIN Commandes ON NCli=NClient

22. SELECT DISTINCT Nom, Adresse, Ville, Entreprise 
   FROM Clients JOIN Commandes ON NClient=NCli
   WHERE Ville='Toulouse'
 
23. SELECT * FROM Clients JOIN
     (SELECT NCli AS NClient FROM Clients
      EXCEPT
      SELECT NClient FROM Commandes)
    ON NCli=NClient
    WHERE Ville='Toulouse'
Il reste les clients 33, 41, 44.
ou mieux  !!
 SELECT Ville, count(*) 
   FROM Clients JOIN Commandes ON NCli=NClient
   GROUP BY Ville

24. SELECT * FROM Produits JOIN Details ON NPro=NProduit

25. SELECT NPro, Libelle, SUM(Quantite) AS NComTotal 
   FROM Produits JOIN Details ON NPro=NProduit 
   GROUP BY NPro, Libelle

 26. SELECT NPro, Libelle, SUM(Quantite) AS NComTotal
   FROM Produits JOIN Details ON NPro=NProduit
   GROUP BY NPro, Libelle
   HAVING NComTotal>100
\end{SQL}

27. SELECT NPro, Libelle, COUNT(*), 
          MIN(Quantite), AVG(Quantite), Max(Quantite)
   FROM Produits JOIN Details ON NPro=NProduit
   GROUP BY NPro, Libelle
\end{SQL}

28. SELECT NClient, SUM(Quantite) AS QTotale, COUNT(*) AS NbCom
%    FROM Details JOIN Commandes ON NCom=NCommande
%    GROUP BY NClient
%    HAVING QTotale>200 OR NbCom>10


% On pouvait aussi utiliser {UNION}. 

28. SELECT AVG(NbProCom) FROM
%     (SELECT NCommande, SUM(Quantite) AS NBProCom
%      FROM Produits JOIN Details ON NPro=NProduit
%      GROUP BY NCommande)

% On obtient une moyenne de $21,46$ articles commandés par commande. On peut
% vérifier ce nombre car on connaît le nombre total d'articles commandés (3327)
% que l'on divise par le nombre de commandes (155) obtenu par:

%    SELECT COUNT(*) FROM Commandes
 

29. SELECT NClient, Prix, Quantite
   FROM Produits JOIN Commandes JOIN Details
   ON NPro=NProduit AND NCom=NCommande

30. SELECT NClient, Prix*Quantite
   FROM Produits JOIN Commandes JOIN Details
   ON NPro=NProduit AND NCom=NCommande

31. SELECT NClient, SUM(Prix*Quantite) AS PrixTotal
   FROM Produits JOIN Commandes JOIN Details
   ON NPro=NProduit AND NCom=NCommande
   GROUP BY NClient

 32. SELECT Nom, Adresse, Ville, SUM(Prix*Quantite) AS PrixTotal
   FROM Produits JOIN Commandes JOIN Details JOIN Clients
   ON NPro=NProduit AND NCom=NCommande AND NCli=NClient
   GROUP BY NClient

 33. SELECT Nom, Adresse, Ville, 
          SUM(Prix*Quantite)-Compte AS APayer
   FROM Produits JOIN Commandes JOIN Details JOIN Clients
   ON NPro=NProduit AND NCom=NCommande AND NCli=NClient
   GROUP BY NClient

 34. SELECT Nom, Adresse, Ville, 
          SUM(Prix*Quantite)-Compte AS APayer
   FROM Produits JOIN Commandes JOIN Details JOIN Clients
   ON NPro=NProduit AND NCom=NCommande AND NCli=NClient
   GROUP BY NClient
   HAVING APayer>0 


On obtient un tableau avec 34 lignes