Compare inner join and outer join SQL statements

Question

What is the difference between an inner join and outer join? What's the precise meaning of these two kinds of joins?

Answer 1

Check out Jeff Atwood's excellent:

A Visual Explanation of SQL Joins

Marc

Answer 2

Wikipedia has a nice long article on the topic [here](http://en.wikipedia.org/wiki/Join_(SQL))

But basically :

• Inner joins return results where there are rows that satisfy the where clause in ALL tables
• Outer joins return results where there are rows that satisfy the where clause in at least one of the tables