Working with RTRIM in MySQL

Intro

MySQL provides the RTRIM function to remove extra white space to the right of the string. In this article, we will learn how to use RTRIM with MySQL.

The Syntax

The basic syntax of a RTRIM is as follows:

SELECT RTRIM(string_name, length);

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.

A Simple Example

The basic example is straight forward. We can pass a string into the RTRIM function and it will remove the white space on the right.

SELECT RTRIM('Hello World!    ');

RTRIM('Hello World! ')
Hello World!

We can also use MySql variables with RTRIM

SET @str = 'Hello World!   ';
SELECT 
    RTRIM(@str);

RTRIM(@str)
Hello World!

That's the gist of using the RTRIM function. We can also use RTRIM on a table. If you would like to try that, let's first set up a table.

Creating a DB

In this article, we will need some data to work with. We will be using the sample db provided here: https://dev.mysql.com/doc/employee/en/. However, we will only enter what we need rather than import the whole db.

With the SQL tab open (or your own sql cli going), let's first create our DB and select it.

create DATABASE if not EXISTS sakila;

USE sakila;

CREATE TABLE employees (
    emp_no      INT             NOT NULL,
    birth_date  DATE            NOT NULL,
    first_name  VARCHAR(14)     NOT NULL,
    last_name   VARCHAR(16)     NOT NULL,
    gender      VARCHAR(16)     NOT NULL,    
    hire_date   DATE            NOT NULL,
    PRIMARY KEY (emp_no)
);

Now, let's enter a few rows. These all have right white space added for our string.

INSERT INTO employees VALUES 
(10001,'1953-09-02','Georgi     ','Facello   ','M','1986-06-26'),
(10002,'1964-06-02','Bezalel   ','Simmel   ','F','1985-11-21'),
(10003,'1959-12-03','Parto','Bamford  ','M','1986-08-28'),
(10004,'1954-05-01','Chirstian  ','Koblick  ','M','1986-12-01'),
(10005,'1955-01-21','Kyoichi','Maliniak   ','M','1989-09-12');

An Example

Now that we are set up, we can use RIGHT on our columns.

SELECT RTRIM(first_name) FROM employees;

RTRIM(first_name)
Georgi
Bezalel
Parto
Chirstian
Kyoichi