The type of string_expression must be CHARACTER, VARCHAR, or CLOB. For non-character data types, the function returns an error.
By default, Teradata Database performs implicit type conversion on a UDT argument that has an implicit cast that casts between the UDT and a predefined character type.
To define an implicit cast for a UDT, use the CREATE CAST statement and specify the AS ASSIGNMENT clause.
Implicit type conversion of UDTs for system operators and functions, including CHARACTER_LENGTH, is a Teradata extension to the ANSI SQL standard. To disable this extension, set the DisableUDTImplCastForSysFuncOp field of the DBS Control Record to TRUE.