Cheat Sheets
Visual references you can actually use, the concepts that matter, distilled to a page.
SQL Foundations: The Logic Behind It
The biggest breakthrough in SQL is not more syntax. It is understanding how SQL thinks. Five foundations every analyst should master: the logical execution order (FROM, WHERE, GROUP BY, HAVING, SELECT, ORDER BY, LIMIT), subqueries and query contexts, why SQL is declarative, why it thinks in sets not rows, and how NULL and three-valued logic actually work.
The 20% of SQL That Does 80% of the Work
Five SQL clauses answer most business questions: SELECT, WHERE, GROUP BY, JOIN and HAVING. But the thing that actually unblocks people isn't the syntax, it's knowing that SQL doesn't execute in the order you write it. This cheat sheet covers the five essential clauses, SQL's true execution order (FROM → WHERE → GROUP BY → HAVING → SELECT → ORDER BY), why WHERE and HAVING aren't interchangeable, and a worked query that uses all of them.
Prompt Engineering Reference
System prompts, few-shot, and structured output at a glance.
Agentic Design Patterns
Memory, planning, tool use, the building blocks of production agents.