Lesson 13. Working with Subqueries
In this lesson, you’ll learn what subqueries are and how to use them.
Understanding Subqueries
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.
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 examples.
Filtering by Subquery
The database tables used in all the lessons in this book are relational tables. (See ...
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