One of the most common tasks of MySQL database analysts and administrators is extracting records from several tables according to specific conditions. It could be quite a sophisticated operation requiring you to write and execute multiple queries. Or, you can use JOINs.

JOINs help you fetch data from several tables, which share a common field, and get a single result. As MySQL tables are connected logically and linked with a common key value, JOINs can provide you with the data you need from several tables by using just one query.

Why MySQL JOINs are helpful:

• Speed: JOINs allow you to use a single query instead of many simple queries run one by one. The result delivered is the same.
• Effectiveness: In MySQL, JOIN clauses perform much better because they work through indexing.
• Less load: JOINs help users reduce the number of data transfers between a MySQL server and a target application. Respectively, it reduces the server load.

Database developers, admins, and analysts use JOINs every day — to combine sets of data, process and find data patterns in vast databases, normalize table structures, etc. Therefore, anyone who works with databases as part of their functional role needs a solid understanding of how to apply this clause.

This white paper is created to equip you with the best professional practices for using JOINs and help you master them quickly and easily.