Beginning Microsoft SQL Server 2008 ... - S3 Tech Training

Chapter 4: JOINs
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Using an INNER JOIN, the result set would look like this:
FilmID FilmName YearMade FirstName LastName
1 My Fair Lady 1964 Rex Harrison
1 My Fair Lady 1964 Audrey Hepburn
2 Unforgiven 1992 Clint Eastwood
Notice that Bogey was left out of this result set. That’s because he didn’t have a matching record in the
Films table. If there isn’t a match in both tables, then the record isn’t returned. Enough theory — let’s
try this out in code.
The preferred code for an INNER JOIN looks something like this:
SELECT
FROM
[ON ]
This is the ANSI syntax, and you’ll have much better luck with it on non-SQL Server database systems
than you will if you use the proprietary syntax required prior to version 6.5 (and still used by many
developers today). We’ll take a look at the other syntax later in the chapter.
It is probably worth noting that the term “ANSI syntax” is there because the original foundations of it
were created as part of an ANSI standard in the mid 1980s. That standard has since been taken over by
the International Standards Organization (ISO), so you may hear it referred to based on either standards
organization.
Fire up the Management Studio and take a test drive of INNER JOINs using the following code against
AdventureWorks2008:
SELECT *
FROM Person.Person
INNER JOIN HumanResources.Employee
ON Person.Person.BusinessEntityID = HumanResources.Employee.BusinessEntityID
The results of this query are too wide to print in this book, but if you run this, you should get something
on the order of 290 rows back. There are several things worth noting about the results:
❑ The BusinessEntityID column appears twice, but there’s nothing to say which one is from
which table.
❑ All columns were returned from both tables.
❑ The first columns listed were from the first table listed.