SQL Server LOWER() Function

 The LOWER() function in SQL Server is used to convert all uppercase characters in a string to lowercase. This function is commonly used for case-insensitive comparisons, formatting, or standardizing string data.

Syntax:

LOWER(string_expression)

• string_expression: The input string or column value that you want to convert to lowercase.

Example Usage:

1. Convert a single string to lowercase:

SELECT LOWER('SQL SERVER FUNCTION');
-- Output: 'sql server function'

2. Use with a table column:

SELECT LOWER(ColumnName) AS LowercaseColumn
FROM TableName;

3. Use for case-insensitive comparisons:

SELECT *
FROM Users
WHERE LOWER(Username) = 'john_doe';

This ensures the comparison works regardless of the case in the Username column.

Notes:

• Non-alphabetic characters (e.g., numbers, symbols) remain unchanged.
• If the input is NULL, the function returns NULL.

The LOWER() function is a helpful tool when working with case-insensitive data or ensuring uniformity in string values.