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SQL Server Tips by Burleson |
Outer right
An outer right join is similar to the outer left but returning all
the rows from the table on the right instead of the left.
Example: To display all titles, even the ones with no publishers in
the publisher's database, in this situation the publisher will be
NULL.
SELECT dbo.publishers.pub_name,
dbo.titles.title
FROM dbo.publishers RIGHT OUTER JOIN
dbo.titles ON dbo.publishers.pub_id = dbo.titles.pub_id
Does it mean that an outer right join will become an outer left join
if the tables switch places around the JOIN clause? Yes, it is that
simple for joins between two tables but it gets more complicated if
more tables are involved. The next example proves that an outer
right join and an outer left join return identical results by
switching the places of the joined tables:
SELECT dbo.publishers.pub_name,
dbo.titles.title
FROM dbo.titles LEFT OUTER JOIN
dbo.publishers ON dbo.publishers.pub_id = dbo.titles.pub_id
The above book excerpt is from:
Super SQL
Server Systems
Turbocharge Database Performance with C++ External Procedures
ISBN:
0-9761573-2-2
Joseph Gama, P. J. Naughter
http://www.rampant-books.com/book_2005_2_sql_server_external_procedures.htm |
