Beginning SQL

Category FirstName LastName
War Jenny Jones
Thriller John Jones
Romance Doris Night
Historical Doris Night
Thriller Susie Simons
Horror Susie Simons
Historical Susie Simons
Romance Katie Smith
War Katie Smith
What you have at the moment is a results set that details each member’s favorite film categories. What
you need, though, is a list of all the films under each category for each member. To produce such a list,
you need to link to the Films table where all the film data is stored. The field that links the two tables is
the CategoryId field, which was a primary key field in the Category table and a foreign key field in the
Films table when you designed the database. You need to add the following INNER JOIN to the bottom
of the current INNER JOIN list:
INNER JOIN Films
ON Films.CategoryId = Category.CategoryId
Extracting Information
This is the final link needed. It joins the Films table to the results and allows details such as FilmName
and YearReleased to be included in the results:
SELECT MemberDetails.FirstName, MemberDetails.LastName, Category.Category,
FilmName, YearReleased
FROM ((FavCategory INNER JOIN Category
ON FavCategory.CategoryId = Category.CategoryId)
INNER JOIN MemberDetails
ON FavCategory.MemberId = MemberDetails.MemberId)
INNER JOIN Films
ON Films.CategoryId = Category.CategoryId
ORDER BY MemberDetails.LastName, MemberDetails.FirstName;
Note the brackets around the joins, which ensures that the code works with MS Access. The other
database systems don’t need the brackets, and they can be left off. Notice also that the results of each join
are bracketed. The first join is bracketed on its own, then this is bracketed together with the second join,
and finally the third join links to these results and doesn’t need brackets
The final SQL provides the following results set that details all the films in each member’s favorite film
category:
97