PostgreSQL provides the lower function to transform a string into all lower case letters. In this article, we will learn how to use LOWER in PostgreSQL.
The basic syntax of a LOWER is as follows:
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: 'postgres:latest' ports: - 5432:5432 environment: POSTGRES_USER: username POSTGRES_PASSWORD: password POSTGRES_DB: default_database volumes: - psqldata:/var/lib/postgresql phpmyadmin: image: phpmyadmin/phpmyadmin links: - db environment: PMA_HOST: db PMA_PORT: 3306 PMA_ARBITRARY: 1 restart: always ports: - 8081:80 volumes: psqldata:
Now, navigate to
http://localhost:8081/ to access phpMyAdmin. Then log in with the username
root and pass
Click the SQL tab and you are ready to go.
The simple example is to lower case a string literal. Here is an example.
select lower('Hello World!') as lower_string;
We can also run lower on a column. Below we create an employee table.
CREATE TABLE employees ( first_name VARCHAR (50) NOT NULL, last_name VARCHAR (50) NOT NULL ); insert into employees (first_name, last_name) values ('Keith', 'Holliday'), ('Jon', 'Doe'), ('Jane', 'Doe');
We can now run the lower function on the columns.
select lower(first_name) as FirstName, lower(last_name) as LastName from employees e;