The Compact Rosetta Guide to SQL

The same query, three ways - because your stack probably isn't just one dialect.

PostgreSQL, MySQL, and Snowflake all speak SQL - but rarely the same SQL. A join that works cleanly in one dialect throws a syntax error in another; a window function behaves differently depending on the engine; a "standard" clause turns out to be a vendor extension nobody warned you about.

The Compact Rosetta Guide to SQL is a single reference that walks the entire language - from foundational logic through advanced analytical patterns - with every concept shown side by side across all three dialects at once.

Inside, you'll find:

• Core SQL logic: filtering, joins, subqueries, and the query evaluation order that explains half of SQL's "gotchas"
• Aggregation and window functions, including ranking, frame clauses, and the QUALIFY clause
• Advanced structures: recursive CTEs, pivoting, lateral joins, and JSON handling
• Real analytical patterns: running totals, cohort analysis, gaps-and-islands, sessionization
• A dense quick-reference cheat table for daily lookup once you already know the concepts
• Clear cautions on version-specific quirks and dialect divergences, verified against current documentation

Whether you're learning SQL for the first time, migrating between engines, or just tired of guessing which dialect you're supposed to be writing today, this guide is built to sit open next to your editor - not on a shelf.