Anthony DeBarros - Practical SQL, 2nd Edition: A Beginners Guide to Storytelling with Data

Since the publication of the first edition of Practical SQL, Ive received kind notes about the book from readers around the world. One happy reader said it helped him ace SQL questions on a job interview. Another, a teacher, wrote to say that his students remarked favorably about having the book assigned for class. Others just wanted to say thanks because they found the book helpful and a good read, two pieces of feedback that will warm the heart of most any author.

I also sometimes heard from readers who hit a roadblock while working through an exercise or who had trouble with software or data files. I paid close attention to those emails, especially when the same question seemed to crop up more than once. Meanwhile, during my own journey of learning SQLI use it every day at workId often discover a technique and wish that Id included it in the book.

With all that in mind, I approached the team at No Starch Press with the idea of updating and expanding Practical SQL into a second edition. Im thankful they said yes. This new version of the book is more complete, offers stronger guidance for readers related to software and code, and clarifies information that wasnt as clear or presented as accurately as it could have been. The book has been thoroughly enjoyable to revisit, and Ive learned much along the way.

This second edition includes numerous updates, expansions, and clarifications in every chapter. Throughout, Ive been careful to note when code syntax adheres to the SQL standardmeaning you can generally use it across database systemsor when the syntax is specific to the database used in the book, PostgreSQL.

The following are among the most substantial changes:

• Two chapters are new. Chapter 1, Setting Up Your Coding Environment, details how to install PostgreSQL, pgAdmin, and additional PostgreSQL components on multiple operating systems. It also shows how to obtain the code listings and data from GitHub. In the first edition, this information was located in the introduction and occasionally missed by readers. Chapter 16, Working with JSON Data, covers PostgreSQLs support for the JavaScript Object Notation data format, using datasets about movies and earthquakes.
• In Chapter 4 on data types, Ive added a section on IDENTITY, the ANSI SQL standard implementation for auto-incrementing integer columns. Throughout the book, IDENTITY replaces the PostgreSQL-specific serial auto-incrementing integer type so that code examples more closely reflect the SQL standard.
• Chapter 5 on importing and exporting data now includes a section about using the WHERE keyword with the COPY command to filter which rows are imported from a source file to a table.
• Ive removed the user-created median() function from Chapter 6 on basic math in favor of focusing exclusively on the SQL standard percentile_cont() function for calculating medians.
• In Chapter 7 on table joins, Ive added a section covering the set operators UNION, UNION ALL, INTERSECT, and EXCEPT. Additionally, Ive added a section covering the USING clause in joins to reduce redundant output and simplify query syntax.