SQL Playground

What exactly runs here?

Two real database engines, compiled to WebAssembly and running inside your browser tab:

Nothing is simulated: every query, result and error comes from the real engine. Nothing leaves your browser either — there is no server behind this page. Reset database puts the sample data back.

How to use it

1. Pick the engine and a sample database: Company (employees, departments, projects), Shop (customers, products, orders) or an empty one.
2. Write SQL in the editor — table and column names autocomplete — and press Run or Ctrl+Enter. You can run several statements at once, separated by ;.
3. Each statement gets its own result: rows for SELECT, “rows affected” for INSERT/UPDATE/DELETE, OK for everything else.
4. Click a table on the left to preview it, or an example to load and run it.

The link in your address bar contains your query, so you can share it.

Practice permissions (PostgreSQL)

Users and GRANT behave exactly like on a PostgreSQL server. Try this on the Company database:

CREATE ROLE analyst LOGIN;
GRANT SELECT ON employees TO analyst;
SET ROLE analyst;
SELECT count(*) FROM employees;     -- works
DELETE FROM employees WHERE id = 20; -- ERROR: permission denied for table employees

Then run RESET ROLE; to become the superuser again. The sidebar always shows who you are connected as. SQLite has no users or permissions, so this only works on PostgreSQL.

FAQ

Is my data saved?

No. The database lives in your browser tab’s memory and starts fresh when you reload the page — perfect for experimenting, DROP TABLE included.

Why does an error still change my data?

When you run several statements, the ones before the failing statement have already been executed — just like in psql or the sqlite3 shell. Wrap them in BEGIN; … COMMIT; to make them all-or-nothing.

How big is the download?

PostgreSQL is a few megabytes and SQLite about one; both download only when you open this page, and your browser caches them afterwards.

Where can I practice with set tasks?

In the SQL Exercises, on the same engines and sample data, with your results checked as you go.

Can I run the examples in the articles?

Yes. SQL examples in the PostgreSQL articles have a Run button: the block runs right under it, on the same engine, loaded on the first click, with the article’s sample data and the examples above it on the page. “Run it in the SQL Playground” opens them here instead, to change and explore.