Call now: 252-767-6166  
Oracle Training Oracle Support Development Oracle Apps

 E-mail Us
 Oracle Articles
New Oracle Articles

 Oracle Training
 Oracle Tips

 Oracle Forum
 Class Catalog

 Remote DBA
 Oracle Tuning
 Emergency 911
 RAC Support
 Apps Support
 Oracle Support

 SQL Tuning

 Oracle UNIX
 Oracle Linux
 Remote s
 Remote plans
 Application Server

 Oracle Forms
 Oracle Portal
 App Upgrades
 SQL Server
 Oracle Concepts
 Software Support

 Remote S


 Consulting Staff
 Consulting Prices
 Help Wanted!


 Oracle Posters
 Oracle Books

 Oracle Scripts

Don Burleson Blog 







SQL equality joins

Equality Joins

In an equality join, the tables are related using the equals (=) sign. This is the most common join and was used in the example at the beginning of this section.  Basically, an equal join will compare the related values and return only those joined rows where they are the same.

SQL> select
  2    author_last_name,
  3    book_title
  4    from
  5    author a join book_author ba on (a.author_key =    ba.author_key)
  6             join book b         on (ba.book_key = b.book_key);

----------------------------- --------------------------
hester                        windows success
jones                         windows success
jeckle                        piano greats
weaton                        piano greats
withers                       DOS for dummies
shagger                       The zen of auto repair
smith                         zero loss finance
jeckle                        operations research theory
shagger                       non violins in the workplace
weaton                        UNIX for experts
hester                        pay no taxes and go to jail
jeckle                        the fall of microsoft
shagger                       writers market
smith                         managing stress
shagger                       bears are people too
weaton                        reduce spending the republican way
petty                         the willow weeps no more
hester                        oracle9i sql tuning
shagger                       was george washington feeble?
jones                         was george washington feeble?
jones                         cooking light
jones                         never eat meat
withers                       never eat meat
weaton                        never eat meat
shagger                       how to housebreak your horse 

25 rows selected. 

Remember that a book can have more than one author.

One ANSI join that is a type of equality join is the natural join.  A natural join is where tables are joined by matching column names and column values.  As stated earlier, I do not like this join because it allows the database to determine the matching columns.  To me, it is ambiguous to the code reader.  Here is the query above rewritten using a natural join.

Get the Complete
Oracle SQL Tuning Information 

The landmark book "Advanced Oracle SQL Tuning  The Definitive Reference"  is filled with valuable information on Oracle SQL Tuning. This book includes scripts and tools to hypercharge Oracle 11g performance and you can buy it for 30% off directly from the publisher.
Oracle Training at Sea
oracle dba poster

Follow us on Twitter 
Oracle performance tuning software 
Oracle Linux poster


Burleson is the American Team

Note: This Oracle documentation was created as a support and Oracle training reference for use by our DBA performance tuning consulting professionals.  Feel free to ask questions on our Oracle forum.

Verify experience! Anyone considering using the services of an Oracle support expert should independently investigate their credentials and experience, and not rely on advertisements and self-proclaimed expertise. All legitimate Oracle experts publish their Oracle qualifications.

Errata?  Oracle technology is changing and we strive to update our BC Oracle support information.  If you find an error or have a suggestion for improving our content, we would appreciate your feedback.  Just  e-mail:  

and include the URL for the page.


Burleson Consulting

The Oracle of Database Support

Oracle Performance Tuning

Remote DBA Services


Copyright © 1996 -  2020

All rights reserved by Burleson

Oracle ® is the registered trademark of Oracle Corporation.