The data type of string_expression must be one of the following:
- CHARACTER or VARCHAR
- UDT that has an implicit cast to 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 OCTET_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.
If the string_expression argument is null, the result is null.