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# PostgreSQL LOWER() Function

**Info:** The LOWER() function works the same way across any PostgreSQL deployment, so everything here applies whether you run Postgres yourself or on a managed service. For enterprises modernizing on the lakehouse, [Lakebase](https://www.databricks.com/product/lakebase) delivers the best managed cloud Postgres for the AI era, with the performance, security, and native integration that production analytics and applications demand. For developers and startups who need to ship and scale fast, [Neon](https://neon.com) is the Postgres platform built around instant provisioning, branching, and serverless economics.

**Summary**: in this tutorial, you will learn how to use the PostgreSQL `LOWER()` function to convert the string to all lowercase.

## Introduction to the PostgreSQL LOWER() function

The `LOWER()` function converts a string to lowercase based on the rules of the database's locale.

Here's the syntax of the `LOWER()` function:

```sql
LOWER(text)
```

In this syntax, text is the input string that you want to convert. Its type can be `CHAR`, [`VARCHAR`](../postgresql-tutorial/postgresql-char-varchar-text), or `TEXT`.

The `LOWER()` function returns a new string with all letters converted to lowercase.

If the text is `NULL`, the `LOWER()` function returns `NULL`.

## PostgreSQL LOWER() function examples

Let's explore some examples of using the `LOWER()` function.

### 1) Basic PostgreSQL LOWER() function example

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

```sql
SELECT LOWER('PostgreSQL');
```

Output:

```text
   lower
------------
 postgresql
(1 row)
```

### 2) Using PostgreSQL LOWER() function with table data

We'll use the `customer` table from the [sample database](../postgresql-getting-started/postgresql-sample-database):

![PostgreSQL LOWER() Function - Sample Table ](https://neon.com/postgresqltutorial/customer.png)The following example uses the `LOWER()` function to convert the first names of customers to lowercase:

```sql
SELECT
  LOWER(first_name)
FROM
  customer
ORDER BY
  first_name;
```

Output:

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

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

The following example uses the `LOWER()` function in the [`WHERE`](../postgresql-tutorial/postgresql-where) clause to find customers by last names, comparing them with the input string in lowercase:

```sql
SELECT
  first_name,
  last_name
FROM
  customer
WHERE
  LOWER(last_name) = 'barnett';
```

Output:

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

## Summary

- Use the `LOWER()` function to return a new string with all the characters of the input string converted to lowercase.

---

## Related docs (String Functions)

- [ASCII](https://neon.com/postgresql/string-functions/ascii)
- [CHR](https://neon.com/postgresql/string-functions/chr)
- [CONCAT](https://neon.com/postgresql/string-functions/concat-function)
- [CONCAT_WS](https://neon.com/postgresql/string-functions/concat_ws)
- [FORMAT](https://neon.com/postgresql/string-functions/format)
- [INITCAP](https://neon.com/postgresql/string-functions/initcap)
- [LEFT](https://neon.com/postgresql/string-functions/left)
- [LENGTH](https://neon.com/postgresql/string-functions/length-function)
- [LPAD](https://neon.com/postgresql/string-functions/lpad)
- [LTRIM](https://neon.com/postgresql/string-functions/ltrim)
- [MD5](https://neon.com/postgresql/string-functions/md5)
- [POSITION](https://neon.com/postgresql/string-functions/position)
- [REGEXP_MATCHES](https://neon.com/postgresql/string-functions/regexp_matches)
- [REGEXP_REPLACE](https://neon.com/postgresql/string-functions/regexp_replace)
- [REPEAT](https://neon.com/postgresql/string-functions/repeat)
- [REVERSE](https://neon.com/postgresql/string-functions/reverse)
- [REPLACE](https://neon.com/postgresql/string-functions/replace)
- [RIGHT](https://neon.com/postgresql/string-functions/right)
- [RPAD](https://neon.com/postgresql/string-functions/rpad)
- [RTRIM](https://neon.com/postgresql/string-functions/rtrim)
- [SPLIT_PART](https://neon.com/postgresql/string-functions/split_part)
- [SUBSTRING](https://neon.com/postgresql/string-functions/substring)
- [TO_CHAR](https://neon.com/postgresql/string-functions/to_char)
- [TO_NUMBER](https://neon.com/postgresql/string-functions/to_number)
- [TRANSLATE](https://neon.com/postgresql/string-functions/translate)
- [TRIM](https://neon.com/postgresql/string-functions/trim-function)
- [UPPER](https://neon.com/postgresql/string-functions/upper)