Beginning SQL

Chapter 10
Types of Views
Given that most SQL statements can be coerced into a view, you can build up many different types of views
to fit your needs. But first, for the purposes of simplifying your life, build a base view that pulls all of the
fields you need from a set of tables. Later in the chapter, you build other views based on that original view.
Suppose that you need to analyze meeting attendance. The first, or base, view pulls data from
MemberDetails, Attendance, and Location. The user is generally not interested in the table’s primary
and foreign keys, so you just pull all the data fields from each table. You are not going to perform any filtering
or ordering on the base data; you will just pull the required data. This may not be efficient for
large tables or results sets. This strategy is not recommended in general, but it makes your results sets
more interesting for your limited data.
Table Join Views
Table join views are views that join related tables back together in order to pull specific fields out of the
related tables and display a view across more than one table. Getting all of the tables joined, with lookup
tables, outer joins where needed, and all the other little things required to gather data from a half dozen
or more tables, can take a while to get correct. Once correct, there may be little need to do it over and
over again. Queries that join multiple tables are called base queries because they form the base of other
queries that simply need to use all this data. A single base query may serve to gather data for dozens of
other queries.
Base View
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The SQL for a base view might look like the following (in SQL Server):
SELECT dbo.MemberDetails.LastName, dbo.MemberDetails.FirstName,
dbo.MemberDetails.DateOfBirth, dbo.MemberDetails.Street, dbo.MemberDetails.City,
dbo.MemberDetails.State, dbo.MemberDetails.ZipCode, dbo.MemberDetails.Email,
dbo.MemberDetails.DateOfJoining, dbo.Attendance.MeetingDate,
dbo.Attendance.MemberAttended, dbo.Location.Street AS [Meeting Street],
dbo.Location.City AS [Meeting City], dbo.Location.State AS [Meeting State]
FROM dbo.MemberDetails
INNER JOIN dbo.Attendance
ON dbo.MemberDetails.MemberId = dbo.Attendance.MemberId
INNER JOIN dbo.Location
ON dbo.Attendance.LocationId = dbo.Location.LocationId
Notice that SQL Server places a ton of qualifier data in the SQL statement, the dbo.MemberDetails
part. In some instances, the table qualifiers are a necessity, specifically when you pull identical field
names from different tables, such as City from MemberDetails and from Location. In any event, SQL
statements like this can be a little tough to wade through.
Once you have the SQL statement working, however, you can now add the CREATE VIEW statement and
use this SQL to build a named view.
CREATE VIEW dbo.MemberAttendance AS
SELECT dbo.MemberDetails.LastName, dbo.MemberDetails.FirstName,
dbo.MemberDetails.DateOfBirth, dbo.MemberDetails.Street, dbo.MemberDetails.City,
dbo.MemberDetails.State, dbo.MemberDetails.ZipCode, dbo.MemberDetails.Email,
dbo.MemberDetails.DateOfJoining, dbo.Attendance.MeetingDate,
dbo.Attendance.MemberAttended, dbo.Location.Street AS [Meeting Street],
dbo.Location.City AS [Meeting City], dbo.Location.State AS [Meeting State]