What is Clickhouse

Clickhouse is column database.

Clickhouse is Online Analytical Processing (OLAP) Database.

Usually use for analytics and logging monitoring.

Syntax feels similar to Relational Databases like PostgreSQL and MySQL.

Main feature is able to analyze millions of data in seconds.

Main feature is able to analyze millions of data in seconds.

If not specify engine will default to MergeTree.

It is normal to have duplicate primary keys.

How to install Clickhouse

brew install clickhouse/clickhouse/clickhouse

Start Clickhouse service

brew services start clickhouse

Enter Clickhouse CLI

clickhouse client

Create database

CREATE DATABASE IF NOT EXISTS learning

Use created database

use learning

Create table

create table messages (id UInt32, timestamp DateTime, message String) ENGINE = MergeTree PRIMARY KEY id

Show tables

show tables

Insert data into table

INSERT INTO messages VALUES (1, now(), 'Message #1'), (2, now(), 'Message #2'), (3, now(), 'Message #3')

Drop table

drop table messages