Sams Teach Yourself MySQL

Using Temporary Tables

Temporary tables in MySQL can be a powerful means of manipulating a data set. A temporary table exists only for the duration of your MySQL session, after which it is automatically deleted. Otherwise, it works just the same as a regular database table.

You will learn more about creating database tables in Lesson 14, “Creating and Modifying Tables.” For now, consider some examples to simulate different types of a compound query.

Performing a UNION

To join two or more queries using a temporary table, you need to insert the data rows from both queries into the same table.

First, create a new table using the first query to define the columns. The result of this query will also be inserted into the table.

 CREATE TEMPORARY TABLE ...