SQL Cheat Sheet — 68+ PostgreSQL Examples

Complete SQL cheat sheet: SELECT, WHERE, JOINs, GROUP BY, window functions, CTEs, NULL handling, strings & dates — 60+ copy-ready PostgreSQL examples.

SELECT — Basics (6 examples)
WHERE — Filtering (6 examples)
JOINs — Combining Tables (6 examples)
GROUP BY & Aggregates — Aggregates (6 examples)
Window Functions — Analytics (6 examples)
CTEs & Subqueries — Subqueries & CTEs (6 examples)
NULL Handling — NULLs (4 examples)
String Functions — Text (6 examples)
Date Functions — Dates & Times (6 examples)
INSERT / UPDATE / DELETE — Data Modification (6 examples)
Common Patterns — Recipes (6 examples)
CASE — Conditional Logic (4 examples)

All examples are copy-ready PostgreSQL 2026 syntax. Use the SQL practice environment to try them on real data.

How to use this cheat sheet

Each section below is a self-contained reference card. Start with SELECT and WHERE for the fundamentals, move through JOINs and GROUP BY for combining and summarising data, then reach for window functions and CTEs when queries get analytical. Every snippet is valid PostgreSQL you can paste straight into the practice environment and run against live tables.

What's covered

SELECT and column aliases, WHERE filtering (IN, BETWEEN, LIKE), all four JOIN types plus self-joins, GROUP BY with COUNT/SUM/AVG/HAVING, ROW_NUMBER/RANK/PARTITION BY window functions, CTEs and subqueries, NULL handling with COALESCE and NULLIF, string and date functions, INSERT/UPDATE/DELETE, and the everyday patterns that show up in real queries and interviews.

For deeper explanations with diagrams, read the guides on SQL JOINs, window functions, and subqueries vs CTEs on the SQLumina blog.