Database

Postgres Playground

PostgreSQL is an advanced open-source RDBMS that supports complex queries, transactions, and custom extensions..

Get access to the Postgres playground with one click

Welcome to the PostgreSQL Playground!

PostgreSQL 17 on Alpine — the world’s most advanced open-source RDBMS, with JSON support, window functions, CTEs, and 100+ powerful extensions.

Tip: Connect with psql -U codeground -d codeground. Use \? in psql for help and \dt to list tables.

What’s Pre-installed

PostgreSQL 17 server + psql client
Auto-provisioned database: codeground
Credentials: user codeground, password codeground

Quick Start

psql -U codeground -d codeground
\dt
SELECT version();

Common Workflows

-- Create table with constraints
CREATE TABLE products (
  id SERIAL PRIMARY KEY,
  name TEXT NOT NULL UNIQUE,
  price NUMERIC(10,2) CHECK (price > 0),
  created_at TIMESTAMPTZ DEFAULT NOW()
);

-- Insert & query
INSERT INTO products (name, price) VALUES ('Widget', 9.99), ('Gadget', 24.99);
SELECT * FROM products ORDER BY price DESC;

-- Window function
SELECT name, price, RANK() OVER (ORDER BY price DESC) AS rank FROM products;

Advanced Tips

-- JSONB column
CREATE TABLE events (id SERIAL, data JSONB);
INSERT INTO events (data) VALUES ('{"type":"click","user":42}');
SELECT data->>'type' FROM events WHERE (data->>'user')::int > 10;
CREATE INDEX events_data_idx ON events USING GIN (data);

-- CTE and recursive query
WITH RECURSIVE nums AS (
  SELECT 1 AS n UNION ALL SELECT n+1 FROM nums WHERE n < 10
)
SELECT n FROM nums;

-- EXPLAIN ANALYZE
EXPLAIN ANALYZE SELECT * FROM products WHERE price > 10;

Session Notes

Session lasts 1 hour.
PostgreSQL starts in background and is ready within seconds of your session opening.