In this lesson, you’ll learn what joins are, why they are used, and how to create
SELECT statements using them.
One of SQL’s most powerful features is the capability to join tables on the fly within data-retrieval queries. Joins are one of the most important operations you can perform using SQL
SELECT, and a good understanding of joins and join syntax is an extremely important part of learning SQL.
Before you can effectively use joins, you must understand relational tables and the basics of relational database design. What follows is by no means a complete coverage of the subject, but it should be enough to get you up and running.