Working with CHAR in MySQL

Intro

MySQL provides the CHAR function to allow us to convert numbers into characters. The function is simple, but helpful in string processing. In this article, we will learn how to use CHAR in MySQL.

The Syntax

The basic syntax of a CHAR is as follows:

SELECT CHAR(num);

Getting Setup

We will be using docker in this article, but feel free to install your database locally instead. Once you have docker installed, create a new file called docker-compose.yml and add the following.

version: '3'
 
services:
  db:
    image: mysql:latest
    container_name: db
    environment:
      MYSQL_ROOT_PASSWORD: root_pass
      MYSQL_DATABASE: app_db
      MYSQL_USER: db_user
      MYSQL_PASSWORD: db_user_pass
    ports:
      - "6033:3306"
    volumes:
      - dbdata:/var/lib/mysql
  phpmyadmin:
    image: phpmyadmin/phpmyadmin
    container_name: pma
    links:
      - db
    environment:
      PMA_HOST: db
      PMA_PORT: 3306
      PMA_ARBITRARY: 1
    restart: always
    ports:
      - 8081:80

volumes:
  dbdata:

Next, run docker-compose up.

Now, navigate to http://localhost:8081/ to access phpMyAdmin. Then log in with the username root and pass root_pass.

Click the SQL tab and you are ready to go.

An Example

For a list of codes, we can use the following page: https://en.wikipedia.org/wiki/List_of_Unicode_characters. The decimal column will tell us which number to use in our function.

Let's start with a quick example of selecting a capital A.

select CHAR(65);

We aren't restricted to the Latin alphabet. Here is an example of using the @ sign.

select CHAR(174);