Understanding Joins
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 that you can perform using SQL SELECT, and a good understanding of joins and join syntax is an extremely important part of learning SQL.
But before you can effectively use joins, you must understand relational tables and the basics of relational database design. What follows is by no means complete coverage of the subject, but it should be enough to get you up and running.
Understanding Relational Tables
The best way to understand relational tables is to look at a real-world example.
Suppose you had a database table containing a product catalog, with each catalog item ...
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