Practical SQL, 2nd Edition is a beginner-friendly guide to the database programming language SQL. Journalist and data analyst Anthony DeBarros starts with SQL basics, using the free open-source database PostgreSQL and interface pgAdmin, and works through intermediate and advanced topics including statistics, aggregation, cleaning data, GIS and automating tasks. Along the way, you'll use real-world data from the U.S. Census and other government agencies and learn the fundamentals of good database design. This book is ideal for beginners as well as those who know some SQL and want to go deeper.

Practical SQL, 2nd Edition is available in PDF, .mobi, .epub, and classic print formats.

Questions? Please email practicalsqlbook@gmail.com. You can also open an issue in this repository.

Which Edition Are You Using?

The code and data presented here are for the 2nd Edition of Practical SQL, published in 20XX. If you're using the original edition of the book, please use that repository for the appropriate resources. If the cover of your copy does not say, "2nd Edition," then you're using the original edition.

What's Here

Code: All the SQL statements and command-line listings used in each chapter, organized by chapter folders.

Data: CSV and JSON files plus GIS shapefiles for you to import, also organized by chapter. NOTE! See the warning below about opening CSV files with Excel or text editors in the section on Getting the Code and Data.

Exercises: The "Try It Yourself" questions and answers for each chapter, listed separately. Try working through the questions before peeking at the answers!

FAQ, Updates, and Errata: Answers to frequently asked questions, updates, and corrections are noted at faq-updates-errata.md.

Resources: Updates to the book's Appendix on Additional PostgreSQL Resources at resources.md.

Chapters

Chapter 1: Setting Up Your Coding Environment
Chapter 2: Creating Your First Database and Table
Chapter 3: Beginning Data Exploration with SELECT
Chapter 4: Understanding Data Types
Chapter 5: Importing and Exporting Data
Chapter 6: Basic Math and Stats with SQL
Chapter 7: Joining Tables in a Relational Database
Chapter 8: Table Design That Works for You
Chapter 9: Extracting Information by Grouping and Summarizing
Chapter 10: Inspecting and Modifying Data
Chapter 11: Statistical Functions In SQL
Chapter 12: Working With Dates and Times
Chapter 13: Advanced Query Techniques
Chapter 14: Mining Text to Find Meaningful Data
Chapter 15: Analyzing Spatial Data with PostGIS
Chapter 16: Working With JSON Data
Chapter 17: Saving Time with Views, Functions, and Triggers
Chapter 18: Using PostgreSQL from the Command Line
Chapter 19: Maintaining Your Database
Chapter 20: Telling Your Data's Story
Appendix: Additional PostgreSQL Resources

Getting the Code and Data on Your Computer

Non-GitHub Users

You can obtain all the code and data at once by downloading this repository as a .zip file. To do that:

Click the Code button at top right.
Click Download ZIP
Unzip the file on your computer. Place it in a directory that's easy to remember so you can reference it during the exercises that include importing data to PostgreSQL.
For additional instructions, please read Chapter 1 in the book.

Warning about CSV files!: Opening CSV files with Excel could lead to data loss. Excel will remove leading zeros from numbers that are intended to be stored as text, such as zip codes. If you wish to view the contents of a CSV file, only do so with a plain-text editor and be careful not to save the file in an encoding other than UTF-8 (e.g., Notepad.exe on Windows defaults to ANSI).

GitHub Users

GitHub users may want to clone the repository locally and occasionally perform a git pull to receive any updates.