> This page location: String Functions > UPPER
> Full Neon documentation index: https://neon.com/docs/llms.txt

# PostgreSQL UPPER() Function

**Summary**: in this tutorial, you will learn how to use the PostgreSQL `UPPER()` function to convert a string to uppercase.

## Introduction to the PostgreSQL UPPER() function

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

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

```sql
UPPER(text)
```

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

The `UPPER()` function returns a new string with all letters converted to uppercase.

The `UPPER()` function returns `NULL` if the `text` is `NULL`.

Note that to convert a string to lowercase, you use the [LOWER()](https://neon.com/postgresql/postgresql-string-functions/postgresql-lower) function.

## PostgreSQL UPPER() function examples

Let's take some examples of using the `UPPER()` function.

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

The following example uses the `UPPER()` function to convert the string `PostgreSQL` to uppercase:

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

Output:

```text
   upper
------------
 POSTGRESQL
(1 row)
```

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

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

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

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

Output:

```text
    upper
-------------
 AARON
 ADAM
 ADRIAN
 AGNES
 ALAN
...
```

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

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

```sql
SELECT
  first_name,
  last_name
FROM
  customer
WHERE
  UPPER(last_name) = 'BARNETT';
```

Output:

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

## Summary

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

---

## Related docs (String Functions)

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