Embedded services functions follow the implicit data type conversion rules that apply to UDFs. The UDF implicit type conversion rules are more restrictive than the implicit type conversion Vantage normally uses. If a function argument cannot be converted to the required data type by following the UDF implicit conversion rules, it must be explicitly cast. For details, see “Compatible Types” in Teradata Vantage™ - SQL External Routine Programming , B035-1147 .