Re: Advice on SQL and records

From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Mon, 22 Aug 2005 23:24:31 +0200
Message-ID: <430a4271$0$11061$e4fe514c_at_news.xs4all.nl>


fran_beta_at_hotmail.com wrote:
> I'm teaching in computing. A question appeared in a trial paper
> recently and I'm trying to establish whether the suggested answer is
> correct.
>
> The question was:
>
> SELECT Students.Surname, Students.Name
> FROM Courses, Classes, StudentClasses, Students
> WHERE Courses.CourseID="10MA"
>
> AND
> Courses.CourseID=Classes.CourseID
> AND
> Classes.ClassID=StudentClasses.ClassID AND
>
> StudentClasses.StudentID=STudents.StudentID
>
> ORDER BY Students.Surname, Students.Name
>
>
> Which of the tables is likely to contain the most records?
>
> The suggested answer from Courses; Classes; StudentClassses and
> Students was:
>
> StudentClasses
>
> How would this be determined? Why wouldn't Students contain the most
> records?

It depends on what "StudentClasses" means. What does it mean? Received on Mon Aug 22 2005 - 23:24:31 CEST

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