The UPPER function in SQL is used to convert a string to uppercase letters.

Key Points:

• Converts all characters in a string to their uppercase equivalents.

• Useful for case-insensitive comparisons or formatting.

• Works on string (character) data types.

Syntax

UPPER(string_expression)

• string_expression: The string or column value you want to convert to uppercase.

Example

SELECT UPPER('hello world') AS UpperCaseString;-- Result: 'HELLO WORLD'

SELECT UPPER(FirstName) AS UpperFirstNameFROM Employees;

Notes

• Supported by most SQL databases (MySQL, SQL Server, Oracle, PostgreSQL, etc.).

• For lowercase conversion, use LOWER() function.

If you want, I can show you how to use UPPER in queries or combined with other functions!