SQL playground

Playground status

The interactive playground is not built yet. This page describes the intended behavior; the query examples below still work in any SQL engine in the meantime.

It is intentionally scoped to a reliable local execution model for experimentation, not a production-grade database emulator.

What it should help with

testing NULL handling
validating ranking and window logic
comparing ORDER BY behavior with and without tiebreakers
checking partition-by semantics in a controlled environment

Good test queries

SELECT 1 AS id, NULL AS value
UNION ALL
SELECT 2, 'abc';

SELECT
  customer_id,
  ROW_NUMBER() OVER (
    PARTITION BY customer_id
    ORDER BY purchase_date DESC
  ) AS rn
FROM purchases;

Shipping discipline

Before shipping any SQL playground behavior, verify:

engines agree on NULL semantics
ranking ties are documented and stable
PARTITION BY logic is correct
output formatting is predictable and easy to audit