The SQL Workshop

6. JOINS

Overview

This chapter will help you understand the functionality of the various joins and their implementation through examples. By the end of this chapter, you will be able to implement an INNER JOIN to retrieve overlapping data within multiple tables and write LEFT and RIGHT JOIN queries to filter the results that have been obtained from multiple tables. We will also be able to implement a CROSS JOIN to obtain a cartesian product of the table elements; and combine two queries using UNION.

Introduction

In the previous chapter, we saw how the WHERE clause can be used to filter elements and provide us with more control over the data we can retrieve from a table. However, in many cases, not all the data we require can be found in ...