A report must list every training course, including courses nobody has enrolled in yet, with the number of trainees. Which join type keeps every course?
Un rapport doit lister chaque formation, y compris celles où personne ne s'est encore inscrit, avec le nombre de stagiaires. Quel type de jointure garde toutes les formations ?
Answers
ACourses LEFT JOIN EnrolmentsCourses LEFT JOIN Enrolments
BCourses INNER JOIN Enrolments, which returns only the courses that have matching enrolment rowsCourses INNER JOIN Enrolments, qui ne renvoie que les formations ayant des inscriptions correspondantes
CCourses CROSS JOIN EnrolmentsCourses CROSS JOIN Enrolments
DNo join is neededAucune jointure n'est nécessaire
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