Introduction to the PostgreSQL LOWER() function

TheLOWER() function converts a string to lowercase based on the rules of the database’s locale.

Here’s the syntax of theLOWER() function:

LOWER(text)

In this syntax, text is the input string that you want to convert. Its type can beCHAR,VARCHAR, orTEXT.

TheLOWER() function returns a new string with all letters converted to lowercase.

If the text isNULL, theLOWER() function returnsNULL.

PostgreSQL LOWER() function examples

Let’s explore some examples of using theLOWER() function.

1) Basic PostgreSQL LOWER() function example

The following example uses theLOWER() function to convert the string PostgreSQL to lowercase:

SELECT LOWER('PostgreSQL');

Output:

lower------------ postgresql(1 row)

2) Using PostgreSQL LOWER() function with table data

We’ll use thecustomer table from thesample database:

The following example uses theLOWER() function to convert the first names of customers to lowercase:

SELECT  LOWER(first_name)FROM  customerORDER BY  first_name;

Output:

lower------------- aaron adam adrian agnes alan...

3) Using PostgreSQL LOWER() function in the WHERE clause

The following example uses theLOWER() function in theWHERE clause to find customers by last names, comparing them with the input string in lowercase:

SELECT  first_name,  last_nameFROM  customerWHERE  LOWER(last_name)= 'barnett';

Output:

first_name | last_name------------+----------- Carole     | Barnett(1 row)

Summary

• Use theLOWER() function to return a new string with all the characters of the input string converted to lowercase.

Last updated onJanuary 28, 2024

On this page

• Introduction to the PostgreSQL LOWER() function
• PostgreSQL LOWER() function examples
• Summary