Chapter 14. Working with Subqueries

In this chapter, you’ll learn what subqueries are and how to use them.

Understanding Subqueries

Note

Version RequirementsSupport for subqueries was introduced in MySQL 4.1. To use the SQL described in this chapter, you must be running MySQL 4.1 or later.

SELECT statements are SQL queries. All the SELECT statements you have seen thus far are simple queries: single statements retrieving data from individual database tables.

New Term

QueryAny SQL statement. However, the term is usually used to refer to SELECT statements.

SQL also enables you to create subqueries: queries that are embedded into other queries. Why would you want to do this? The best way to understand this concept is to look at a couple of examples. ...

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