This is an interactive book which aims to be the best place on the internet for learning SQL. It is free of charge, free of ads and doesn't require registration or downloads. It helps you learn by running queries against a real-world dataset to complete projects of consequence. It is not a mere reference page — it conveys a mental model for writing SQL.
I expect little to no coding knowledge. Each chapter is designed to take about 30 minutes. As more of the world's data is stored in databases, I expect that this time will pay rich dividends!
The philosophical and technical underpinnings of this project.
Chapter 1 examines Napoleon Beazley's argument against capital punishment. We learn the structure of a SQL query and row operations on a table.
Chapter 2 estimates how many executed inmates may have been innocent. The technical theme is aggregating the entire table.
Chapter 3 studies counties with unusually high numbers of executions. We generalize Chapter 2 by applying aggregations on groups of rows.
Chapter 4 explores extended periods when no executions have occurred. Its theme is extending the table using joins.
Chapter 5 provides closing remarks and a collection of miscellaneous user-added challenge questions.