?
Solved

"Left Join" versus "Outer Join" in MySQL

Posted on 2007-11-16
4
Medium Priority
?
4,177 Views
Last Modified: 2008-02-01
Someone asked me what is the difference between a "Left Join" and an "Outer Join" in MySQL.

My understanding is that they are the same.

Essentially there are three types of join: Left Outer, Right Outer, and Inner. All the others are just names for these.

Is this correct?
0
Comment
Question by:sypder
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
4 Comments
 
LVL 143

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 20301772
outer join, per se, does not exist. you have to specify LEFT / RIGHT OUTER JOIN.

LEFT JOIN / LEFT OUTER JOIN  are the same.
RIGHT JOIN / RIGHT OUTER JOIN are the same.

please see this page for explanations about the different JOIN s:
http://en.wikipedia.org/wiki/Join_(SQL)
0
 
LVL 3

Author Comment

by:sypder
ID: 20302032
Exactly, this is my understanding.

So what does the question "explain the difference between LEFT JOIN and OUTER JOIN" mean. Since like you said there is no OUTER JOIN and a LEFT JOIN is a LEFT OUTER JOIN.

Unless they meant to write INNER JOIN or it is a trick question.
0
 
LVL 143

Accepted Solution

by:
Guy Hengel [angelIII / a3] earned 2000 total points
ID: 20302088
if you study the following mysql document, you will see confirmed that the OUTER keyword is optional, and cannot stand alone:
http://dev.mysql.com/doc/refman/5.0/en/join.html

so, either indeed this is a typo, or a trick question...
0
 
LVL 3

Author Comment

by:sypder
ID: 20302098
Thanks for confirming that. I did read that document.

It was in a job description I was applying for and it listed that knowing the difference was a key skill. So I figured I should be sure I am right before I head in.

Thanks.
0

Featured Post

Get real performance insights from real users

Key features:
- Total Pages Views and Load times
- Top Pages Viewed and Load Times
- Real Time Site Page Build Performance
- Users’ Browser and Platform Performance
- Geographic User Breakdown
- And more

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Creating and Managing Databases with phpMyAdmin in cPanel.
This post contains step-by-step instructions for setting up alerting in Percona Monitoring and Management (PMM) using Grafana.
In this video, Percona Solution Engineer Rick Golba discuss how (and why) you implement high availability in a database environment. To discuss how Percona Consulting can help with your design and architecture needs for your database and infrastr…
In this video, Percona Solutions Engineer Barrett Chambers discusses some of the basic syntax differences between MySQL and MongoDB. To learn more check out our webinar on MongoDB administration for MySQL DBA: https://www.percona.com/resources/we…
Suggested Courses

801 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question