1-14

corrections/chapitre_05/conf.sql

@@ -88,3 +88,35 @@ SELECT *
 FROM Visitor 
 LEFT JOIN Registration ON Visitor.login = Registration.login
 WHERE id_conference IS NULL;
+
+-- 11
+SELECT V.login, firstname, lastname, COUNT(id_conference)
+FROM Visitor AS V
+LEFT JOIN Registration AS R ON V.login = R.login
+GROUP BY V.login;
+
+
+-- 12
+SELECT lastname, firstname, start_date, end_date, name
+FROM Speaker AS S
+INNER JOIN Stay AS ST ON S.login = ST.login
+INNER JOIN Hotel AS H ON ST.id_hotel = H.id_hotel;
+
+-- 13
+SELECT T.title, COUNT(DISTINCT login)
+FROM Topic AS T
+LEFT JOIN Conference AS C ON T.title = C.title
+LEFT JOIN Registration AS R ON C.id_conference = R.id_conference
+GROUP BY T.title;
+
+-- 14
+SELECT C.name, start_date, end_date,
+( 
+    SELECT COUNT(R.login) FROM Registration AS R 
+    WHERE C.id_conference = R.id_conference 
+) AS Visitors, 
+( 
+    SELECT COUNT(P.login) FROM Participation AS P 
+    WHERE C.id_conference = P.id_conference 
+) AS Speakers
+FROM Conference AS C;