LOWER is valid only for character strings or character string expressions. The function does not accept CLOBs and non-character arguments.
By default, Teradata Database performs implicit type conversion on UDT arguments that have implicit casts to predefined character types.
To define an implicit cast for a UDT, use the CREATE CAST statement and specify the AS ASSIGNMENT clause. For more information on CREATE CAST, see Teradata Vantage™ - SQL Data Definition Language Syntax and Examples, B035-1144.
Implicit type conversion of UDTs for system operators and functions, including LOWER, is a Teradata extension to the ANSI SQL standard. To disable this extension, set the DisableUDTImplCastForSysFuncOp field of the DBS Control Record to TRUE.