In this chapter, you learn what subqueries are and how to use them.
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.
Any SQL statement. However, the term is usually used to refer to
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.