SQL Engine does not perform implicit conversion on input arguments to UDFs, UDMs, or external stored procedures (external routines). Arguments do not necessarily have to be exact matches to the parameter types, but they must be compatible. For example, you can pass a SMALLINT argument to an external routine that expects an INTEGER argument because SMALLINT and INTEGER are compatible. To pass a DATE type argument to an external routine that expects an INTEGER argument, you must explicitly cast the DATE type to an INTEGER type. For more information, see Teradata Vantage™ - SQL External Routine Programming, B035-1147.
Some SQL functions and operators require arguments that are exact matches to the parameter types. For details, refer to the documentation for the specific function or operator.