Q
Problem solve Get help with specific problems with your technologies, process and projects.

Multiple outer joins

Is it possible to have more than one outer join in a SQL statement which involves more than two tables involved?

Yes, it is possible. Just look at the following example:

SQL> select o.owner,u.user_id,d.profile,o.object_type,count(*) as num_types
  2  from objects o, users u, db_users d
  3  where o.owner=u.username(+)
  4    and o.owner=d.username(+)
  5    and o.object_type in ('TABLE','INDEX')
  6* group by o.owner,u.user_id,d.profile,o.object_type;

OWNER         USER_ID PROFILE    OBJECT_TYPE         NUM_TYPES
---------- ---------- ---------- ------------------ ----------
OUTLN              11            INDEX                       3
OUTLN              11            TABLE                       3
PEASLAND           18 DEFAULT    TABLE                       2
SYS                   DEFAULT    INDEX                     249
SYS                   DEFAULT    TABLE                     264
SYSTEM                DEFAULT    INDEX                     144
SYSTEM                DEFAULT    TABLE                     108

7 rows selected.

You can clearly see that I've used two outer joins here. Notice the missing information in both the user_id and profile columns indicative of the outer join.

For More Information

  • What do you think about this answer? E-mail the Edtior at tdichiara@techtarget.com with your feedback.
  • The Best Oracle Web Links: tips, tutorials, scripts, and more.
  • Have an Oracle or SQL tip to offer your fellow DBA's and developers? The best tips submitted will receive a cool prize--submit your tip today!
  • Ask your technical Oracle and SQL questions--or help out your peers by answering them--in our live discussion forums.
  • Ask the Experts yourself: Our SQL, database design, Oracle, SQL Server, DB2, metadata, and data warehousing gurus are waiting to answer your toughest questions.

Dig Deeper on Oracle database design and architecture

Have a question for an expert?

Please add a title for your question

Get answers from a TechTarget expert on whatever's puzzling you.

You will be able to add details on the next page.

Start the conversation

Send me notifications when other members comment.

Please create a username to comment.

-ADS BY GOOGLE

SearchDataManagement

SearchBusinessAnalytics

SearchSAP

SearchSQLServer

TheServerSide.com

SearchDataCenter

SearchContentManagement

SearchHRSoftware

Close