16.20 - Variable Mode Table UDFs - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL External Routine Programming

Product
Advanced SQL Engine
Teradata Database
Release Number
16.20
Release Date
April 2020
Content Type
Programming Reference
Publication ID
B035-1147-162K
Language
English (United States)

This section provides guidelines on how to write a Java method for a table UDF that can handle an invocation where the SELECT statement specifies columns from a derived table as input arguments. For example, the following statement invokes table_function_2 using column_1 from the preceding derived table with the t1 correlation name:

SELECT *
FROM ( SELECT column_1
       FROM table_1
       WHERE column_2 > 65 ) AS t1,
     TABLE (table_function_2(t1.column_1)) AS t2 (c1, c2, c3)
WHERE t1.column_3 = t2.c3;
Although this section discusses how to implement a method that only handles variable input arguments, you can write a method that can handle constant and variable input arguments. For details on constant mode table UDFs, see Constant Mode Table UDFs.