Working with MySql Limit and Offset

Intro

We often work with large databases and only want to return a small number of rows to view our data. Mysql provides the LIMIT keyword to help with this. In this article, we will learn how to use LIMIT in MySQL.

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.

Creating a DB

In this article, we will need some data to work with. If you don't understand these commands, don't worry, we will cover them in later articles.

We will be using the sample db provided here: https://dev.mysql.com/doc/sakila/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;

Next, let's create an actor table.

CREATE TABLE actor (
  actor_id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT,
  first_name VARCHAR(45) NOT NULL,
  last_name VARCHAR(45) NOT NULL,
  last_update TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY  (actor_id),
  KEY idx_actor_last_name (last_name)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

And finally, let's enter a few rows.

INSERT INTO actor VALUES 
(1,'PENELOPE','GUINESS','2006-02-15 04:34:33'),
(2,'NICK','WAHLBERG','2006-02-15 04:34:33'),
(3,'ED','CHASE','2006-02-15 04:34:33'),
(4,'JENNIFER','DAVIS','2006-02-15 04:34:33'),
(5,'JOHNNY','LOLLOBRIGIDA','2006-02-15 04:34:33'),
(6,'BETTE','NICHOLSON','2006-02-15 04:34:33'),
(7,'GRACE','MOSTEL','2006-02-15 04:34:33'),
(8,'MATTHEW','JOHANSSON','2006-02-15 04:34:33')

The Basic SQL

The basic sql structure as the following pattern.

SELECT * FROM actor LIMIT 2;

Running this command will ensure we only return the first 2 rows matching our query. Since we did not use and WHERE clause, this should be the first 2 rows in the DB.

Using Offsets

The LIMIT keyword allows us to specify two parameters: one for limiting and one for offsetting. This allows us to load our database in sections, also called paginating.

For example, the following query will return the 2 rows after the first row. In this case, it will be rows 2 and 3. The

SELECT * FROM actor LIMIT 1, 2;

The syntax here can be hard to read and easy to mixup which param means offset. MySQL provides the OFFSET keyword to solve this.

SELECT * FROM actor LIMIT 2 OFFSET 1;`
``

|actor_id|first_name|last_name|last_update|
|--------|----------|---------|-----------|
|2|NICK|WAHLBERG|2006-02-15 04:34:33|
|3|ED|CHASE|2006-02-15 04:34:33|