16.20 - SPECIFIC FUNCTION - Teradata Database - Teradata Vantage NewSQL Engine

Teradata Vantage™ SQL Data Definition Language Syntax and Examples

Teradata Database
Teradata Vantage NewSQL Engine
Release Number
March 2019
Content Type
Programming Reference
Publication ID
English (United States)
Last Update
The specific name of the external UDF to be used to convert source_data_type to target_data_type. The specific_function_name must specify a unique function.
You cannot invoke an SQL UDF from a CREATE CAST or REPLACE CAST request.
If you do not specify a set of data types for a function name, then the specified function must be the only external UDF with that name in the database.
The specified function must satisfy the following conditions:
  • It can have only one parameter.

    Its parameter data type must be the same as source_data_type.

  • Its result data type must be the same as target_data_type.
  • It must be defined to be deterministic.
  • Its function name must identify an external UDF in the SYSUDTLIB database.

Example: Casting Source Data using a UDF

The following CREATE CAST request creates a cast operation that converts the source data type VARCHAR(32) to the target data type circle using the UDF having the specific function name VarcharTocircle.

     CREATE CAST (VARCHAR(32) AS circle)