Head First SQL, 2nd Edition

Chapter 12. Functions and Stored Procedures: Reusable Code

A Note for Early Release Readers

With Early Release ebooks, you get books in their earliest form—the author’s raw and unedited content as they write—so you can take advantage of these technologies long before the official release of these titles.

This will be the 12th chapter of the final book. Please note that the GitHub repo will be made active later on.

If you have comments about how we might improve the content and/or examples in this book, or if you notice missing material within this chapter, please reach out to the editor at [e-mail].

Don’t lose it, reuse it. Retyping roughly the same code over and over gets old fast and feels like needless waste. If you’re ready to embrace a sustainable mindset, this chapter shows you how to save your SQL commands and reuse them later. Functions give you a shortcut to perform a set of stored calculations on brand new inputs. They return computed results, which you can even SELECT as a new column of values. How eco-chic! But as amazing as functions are, they aren’t a cure-all. To modify table data or do other complex actions, you’ll need to write your own stored procedure instead. These parameters and variables aren’t going to upcycle themselves, so turn the page to get started.

Repeating yourself...

As fun as it is to write SQL code, you may grow tired of writing ...