clickhouse-hello-world

name	clickhouse-hello-world
description	Create your first ClickHouse table, insert data, and run analytical queries. Use when starting a new ClickHouse project, learning MergeTree basics, or testing your ClickHouse connection with real operations. Trigger with "clickhouse hello world", "first clickhouse table", "clickhouse quick start", "create clickhouse table", "clickhouse example".
allowed-tools	Read, Write, Edit, Bash(npm:*), Bash(node:*)
version	1.7.0
license	MIT
author	Jeremy Longshore <[e-mail]>
tags	["saas","database","analytics","clickhouse","olap"]
compatibility	Designed for Claude Code

ClickHouse Hello World

Overview

Create a MergeTree table, insert rows with JSONEachRow, and run your first analytical query -- all using the official @clickhouse/client. This is the smoke test that proves your connection works and teaches the four MergeTree concepts (ORDER BY, PARTITION BY, TTL, LowCardinality) reused in every real schema.

Prerequisites

• @clickhouse/client installed and connected (see the clickhouse-install-auth skill for connection setup).
• A reachable ClickHouse server (local Docker, ClickHouse Cloud, or self-hosted) with CLICKHOUSE_HOST / CLICKHOUSE_USER / CLICKHOUSE_PASSWORD set as environment variables.

Instructions

Step 1: Create a MergeTree Table

import { createClient } from '@clickhouse/client';

const client = createClient({
  url: process.env.CLICKHOUSE_HOST ?? 'http://localhost:8123',
  username: process.env.CLICKHOUSE_USER ?? 'default',
  password: process.env.CLICKHOUSE_PASSWORD ?? '',
});

await client.command({
  query: `
    CREATE TABLE IF NOT EXISTS events (
      event_id    UUID DEFAULT generateUUIDv4(),
      event_type  LowCardinality(String),
      user_id     UInt64,
      payload     String,
      created_at  DateTime DEFAULT now()
    )
    ENGINE = MergeTree()
    ORDER BY (event_type, created_at)
    PARTITION BY toYYYYMM(created_at)
    TTL created_at + INTERVAL 90 DAY
  `,
});
console.log('Table "events" created.');

Key concepts: