Beginning SQL

Chapter 3
The overlapping portions of the three data sets form the final results set. The ON statements define the
overlap area, which is summarized as follows:
❑ Every record in the FavCategory table must have a matching record in the Category table with
the same value in the CategoryId field.
❑ Every record in the Category table must have a matching record in the FavCategory table with
the same value in the CategoryId field.
❑ Every record in the FavCategory table must have a matching record in the MemberDetails table
with the same value in the MemberId field.
❑ Every record in the MemberDetails table must have a matching record in the Category table
with the same value in the MemberId field.
Documenting the remaining steps in the SQL in diagram form would consume precious pages, so hopefully
SQL’s set-based nature is clear.
By now, you should be familiar enough with sets and inner joins to try out a few.
Try It Out Using Inner Joins to Form Sets
1. Using the following SQL, generate a list for the film club chairperson of all the members who
don’t live in a city in which the club holds meetings. Don’t forget to create a set diagram.
SELECT MemberDetails.FirstName, MemberDetails.LastName,
MemberDetails.City, MemberDetails.State
FROM MemberDetails INNER JOIN Location
ON (MemberDetails.City Location.City AND MemberDetails.State = Location.State)
OR (MemberDetails.City = Location.City AND MemberDetails.State Location.State)
ORDER BY MemberDetails.LastName;
2. The club’s chairperson also wants a list of all the members who have attended meetings, the
date of attendance, and where the meeting was held. To create the list, use the following SQL:
SELECT
MemberDetails.MemberId,
MemberDetails.FirstName,
MemberDetails.LastName,
Attendance.MeetingDate,
Location.City
FROM
(MemberDetails INNER JOIN Attendance
ON MemberDetails.MemberId = Attendance.MemberId)
INNER JOIN Location ON Location.LocationId = Attendance.LocationId
WHERE Attendance.MemberAttended = ‘Y’
ORDER BY MeetingDate, Location.City, LastName, FirstName;
How It Works
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First, you need to create a list of all members not living in a city in which club meetings are held. The
data for meeting locations resides in the Location table. This information provides one results set. Not