About tsqldocs

tsqldocs is a practical SQL reference: the clauses, functions, joins, window functions, data-writing statements, transactions, and performance topics that shape real queries — plus copy-paste recipes, a browser SQL playground, and an AI assistant that answers from these pages.

How it’s built

  • Every example is runnable. The green “SQL playground” blocks execute against a real SQLite database (compiled to WebAssembly) in your browser, seeded with a small fixed sample schema.
  • Examples are tested before they ship. Each runnable query is checked against SQLite first; ones that only work on other engines are shown as static code with the dialect noted.
  • Edge cases are the point. The gotcha that makes a query wrong in production — a NULL in a NOT IN, a WHERE that turns a LEFT JOIN into an inner one — gets a section, not a footnote.
  • Dialect differences are called out. Where PostgreSQL, MySQL, and SQL Server diverge from the standard or from each other, the page says so.

The AI assistant

The “Ask AI” assistant is grounded in this documentation — it searches these pages and cites the ones it used, rather than answering from training data alone. It’s rate-limited so it can stay free. It can still be wrong; treat its output as a starting point and verify against your own database. See the privacy page for what data the assistant sends and where.

Corrections and requests

Found something wrong, unclear, or missing? That’s the most useful feedback there is:

Independence

tsqldocs is an independently-run project. It is not affiliated with, endorsed by, or sponsored by Oracle, the PostgreSQL Global Development Group, Microsoft, or any database vendor. “SQL,” “PostgreSQL,” “MySQL,” “SQL Server,” and related names are trademarks of their respective owners and are used here only to describe those systems.