Accessing Multiple Tables

Goal

When you have completed this chapter, you will be able to create SQL statements that retrieve data from more than one table.

Summary

Until now, you have been retrieving data from only one table at a time. Often, however, the data you want resides in more than one table. For example, you may want information on the department an employee works in as well as the employee information itself. The join operation allows you to do this.

This section contains the following topics:

What Is a Join Operation?

Joining Tables on Common Columns

Qualifying a Column Name

Qualifying a Table Name

Sorting the Result

Additional Search Criteria in a Join

Things to Remember about Joining Tables

Joining a Table to Itself

Using UNION

Review

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