Please explain MySQL Joins in simple language

Question

Please explain to me joins in simple language. Please do not post a web link as I need to read how a developer understand it, not an author.

Answer 1

I'm interpreting your question to mean joins in a very general sense, not each type of join, so if this is off the mark then I apologize:

Basically, joins enable you to get data from multiple tables in a single query by adding columns to your result set. So if you had the following tables:

Books   (ID, Title, AuthorID)
Authors (ID, Name)

You could get a result set that looked like this:

  Book                    |   Author
'The Sirens of Titan'     | 'Kurt Vonnegut'
'The Old Man and the Sea' | 'Earnest Hemingway'

By joining the two tables together like so:

select Books.Title as Book, Authors.Name as Author
from Books
inner join Authors on Authors.ID = Books.AuthorID

An inner join is the simplest type of join; it may be difficult to understand the point of outer joins without first having a strong grasp of inner joins and their uses.