---
path: docs/spatial-sql-book
title: Spatial SQL with PostGIS and SedonaDB
desc: Twenty-five lessons on spatial SQL, written against a live PostGIS cluster and 440 million OSM features.
---

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# Spatial SQL with PostGIS and SedonaDB

Twenty-five lessons, written against a live PostGIS 3.6 cluster and a planet-scale OSM import. Every query on these pages is one you can run yourself.

The first 4 lessons are open. The rest continue in the app.

| # | Lesson | |
|---|---|---|
| 1 | [Prerequisites: Joins and Big O](/docs/spatial-sql-book/01-prerequisites) |  |
| 2 | [Where Your SQL Runs](/docs/spatial-sql-book/02-where-your-sql-runs) |  |
| 3 | [Geometry Is a Type, Not Two Numbers](/docs/spatial-sql-book/03-geometry-as-a-type) |  |
| 4 | [Degrees Are Not Metres](/docs/spatial-sql-book/04-srid-degrees-metres) |  |
| 5 | [Reading a Schema You Did Not Write](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 6 | [Filtering, Casting and NULL Discipline](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 7 | [Aggregation and the Spatial Aggregates](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 8 | [CTEs and the Shape of a Readable Query](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 9 | [Window Functions Over Spatial Measures](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 10 | [Predicates and the DE-9IM Family](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 11 | [The && Operator and What an Index Can Answer](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 12 | [ST_DWithin, ST_Distance and the KNN Operator](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 13 | [Spatial Joins and LATERAL Nearest-Neighbour](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 14 | [Constructors, Accessors and Editors](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 15 | [Simplification, Tolerance and Broken Topology](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 16 | [Invalid, Empty and NULL Are Three Different Things](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 17 | [Querying the Feature Store](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 18 | [Raw OSM Tags as jsonb](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 19 | [H3 Hex Binning, Server-Side](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 20 | [SedonaDB: When the Table Is a File](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 21 | [Choosing an Engine, and Porting a Query](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 22 | [Why Your Query Is Slow](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 23 | [From Query to Map Layer](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 24 | [Reading What the Assistant Wrote](https://app.gisowl.com/app/register?source=site) | Sign in to read |
| 25 | [What This Cluster Cannot Do Yet](https://app.gisowl.com/app/register?source=site) | Sign in to read |

[Open the lessons in the app](https://app.gisowl.com/app/register?source=site)