LOWER (SSIS Expression)
Applies to: 
SQL Server
SSIS Integration Runtime in Azure Data Factory
Returns a character expression after converting uppercase characters to lowercase characters.
Syntax
LOWER(character_expression)
Arguments
character_expression
Is a character expression to convert to lowercase characters.
Result Types
DT_WSTR
Remarks
LOWER works only with the DT_WSTR data type. A character_expression argument that is a string literal or a data column with the DT_STR data type is implicitly cast to the DT_WSTR data type before LOWER performs its operation. Other data types must be explicitly cast to the DT_WSTR data type. For more information, see Integration Services Data Types and Cast (SSIS Expression).
LOWER returns a null result if the argument is null.
Expression Examples
This example converts a string literal to lowercase characters. The return result is "new york".
LOWER("New York")
This example converts all characters from the Color input column, except the first character, to lowercase characters. If Color is YELLOW, the return result is "Yellow". For more information, see SUBSTRING (SSIS Expression).
LOWER(SUBSTRING(Color, 2, 15))
This example converts the value in the CityName variable to lowercase characters.
LOWER(@CityName)