PostgreSQL – LOWER() function

In PostgreSQL, the LOWER() function is a powerful tool used to convert strings, expressions, or values in a column to lowercase. This function is essential for text normalization, making data comparisons easier and more consistent.

Let’s look into the syntax, and usage of the LOWER() function in PostgreSQL with detailed examples.

What is the LOWER() Function in PostgreSQL?

The LOWER() function takes an input string and converts all the characters to lowercase. This is particularly useful when you need to perform case-insensitive comparisons or store data in a uniform format.

Syntax

LOWER(string or value or expression)

Parameter

• string_or_value_or_expression: This argument can be a string, a value, or an expression that you want to convert to lowercase.

PostgreSQL LOWER function Examples

Let us take a look at some of the examples of LOWER Function in PostgreSQL to better understand the concept.

Example 1: Converting Column Values to Lowercase

The below statement uses LOWER function to get the full names of the films from the ‘Film’ table of the sample database, ie, dvdrental:

SELECT LOWER(title) from film;

Output:

Explanation: Here, the LOWER() function converts the title column values to lowercase.

Example 2: Converting a String to Lowercase

The below statement converts an upper case string to lower case:

SELECT LOWER('GEEKSFORGEEKS');

Output:

Explanation: The LOWER() function converts the input string ‘GEEKSFORGEEKS‘ to ‘geeksforgeeks‘.

Important Points About the PostgreSQL LOWER() Function

• The LOWER() function consistently converts all characters in the input to lowercase.
• The function is useful for making case-insensitive comparisons.
• Use the CAST function to convert non-string values to strings if necessary.
• Applicable to strings, expressions, and column values.