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📚 Knowledge Base & Cookbooks

Analytical SQL
Guides & Cheatsheets

Engine-tested reference guides, mental models, and logic recipes designed for data analysts, analytics engineers, and backend developers tackling complex SQL queries.

Articles & References2

Cheatsheet & Handbook⭐ Flagship Handbook
15 min read

A comprehensive, problem-solving cheatsheet covering SQL logical execution order, 3-valued NULL logic, window frame mechanics, gaps & islands, sessionization, recursive CTEs, anti-joins, and query optimization recipes.

#Execution Order#Window Frames#Gaps & Islands#Sessionization#QUALIFY & Top-N#Recursive CTEs#Anti-Joins#JSON & Arrays
Read Guide & View Cheatsheet →All Levels
Dialect Reference
5 min read

PostgreSQL vs. DuckDB Syntax & Function Guide

Engine Compatibility & Dialect Reference

A developer's guide to function mismatches, strict binder types, implicit vs explicit casting, and column identifier casing between PostgreSQL and DuckDB.

#Date Arithmetic#String Formatting#Type Casting#Identifier Casing#COALESCE vs IFNULL
Read Guide & View Cheatsheet →Foundations

Ready to put these SQL patterns to the test?

Practice on 40+ industry-grade DuckDB SQL challenges with isolated datasets, live AST validation, and the Socratic AI Sensei.

Start Challenges →Explore Tracks