In MySQL, the UPPER() function converts lowercase characters to uppercase, according to the current character set mapping (the default mapping is utf8mb4).

Syntax

The syntax goes like this:

UPPER(str)

Where str is the string to be changed to uppercase.

Example

Here’s an example:

SELECT UPPER('cat');

Result:

+--------------+
| UPPER('cat') |
+--------------+
| CAT          |
+--------------+

As you might expect, if the string already contains any uppercase characters, those characters will remain in uppercase.

Example:

SELECT UPPER('Cat');

Result:

+--------------+
| UPPER('Cat') |
+--------------+
| CAT          |
+--------------+

Database Example

Here’s an example of selecting data from a database and converting it to uppercase:

USE Music;
SELECT 
    ArtistName AS Original, 
    UPPER(ArtistName) AS Uppercase
FROM Artists
LIMIT 5;

Result:

+------------------+------------------+
| Original         | Uppercase        |
+------------------+------------------+
| Iron Maiden      | IRON MAIDEN      |
| AC/DC            | AC/DC            |
| Allan Holdsworth | ALLAN HOLDSWORTH |
| Buddy Rich       | BUDDY RICH       |
| Devin Townsend   | DEVIN TOWNSEND   |
+------------------+------------------+

Binary Strings

This function doesn’t work on binary strings. If you need to use it on a binary string, you’ll need to convert it to a nonbinary string first. Here’s an example:

SET @str = BINARY 'Cat';
SELECT 
  UPPER(@str) AS 'Binary', 
  UPPER(CONVERT(@str USING utf8mb4)) AS 'Nonbinary';

Result:

+--------+-----------+
| Binary | Nonbinary |
+--------+-----------+
| Cat    | CAT       |
+--------+-----------+

The UCASE() Function

The UCASE() function is a synonym for UPPER(). Note that if you use UCASE() within a view, it will be rewritten and stored as UPPER().

Convert to Lowercase

The LOWER() and LCASE() functions work the same way to convert characters to lowercase.