Does the answer lie within? Let’s find out. Joins are great, but sometimes you need to ask your database more than one question at a time. Or take the result of one query and use it as the input to another query. Introducing subqueries as the ultimate compartmentalization tool. Subqueries help you avoid duplicate data, make your queries more dynamic, and even help you score tickets to that sold-out K-pop concert. (Well, not really, but two out of three ain’t bad!) You’ll soon discover how versatile subqueries can be, returning single values, columns, or even tabular results when serving as a derived table. And you’ll learn more about choosing between alternate SQL syntax options like subqueries, joins, or common table expressions (CTEs). It’s all embedded in this chapter, so head ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month, and much more.
