Practical SQL by journalist and data analyst Anthony DeBarros is a beginner-friendly guide to the database programming language SQL. Starting with SQL basics, you'll work 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.

This repository is for the First Edition of Practical SQL, published in 2018. If you're reading the Second Edition, published in 2022, you must use the code and data in the second edition repository. If the cover of your copy does not say, "2nd Edition," then you're using the first edition.

Practical SQL is ideal for beginners as well as those who know some SQL and want to go deeper.

We use PostgreSQL, which is free and open source. PostgreSQL is used by some of the world's largest companies. Its SQL syntax adheres closely to the ANSI SQL standard, and the concepts you learn will apply to most database management systems, including MySQL, Oracle, SQLite, and others. Note that Microsoft SQL Server employs a variant of SQL called T-SQL, which is not covered by Practical SQL.

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

Data: CSV files and 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.

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

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.

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.

Practical SQL is published by No Starch Press and available in PDF, .mobi, .epub, and classic print formats.

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