-- EXO 3
SELECT COUNT(*) FROM (
SELECT DISTINCT numclient, nom, prenom
FROM client 
WHERE
numclient NOT IN (SELECT numclient FROM occupation)
AND
numclient NOT IN (SELECT numclient FROM reservation)
)
;

DELETE FROM client
WHERE
numclient NOT IN (SELECT numclient FROM occupation)
AND
numclient NOT IN (SELECT numclient FROM reservation)
;









