16.20 - Example: Function Selection for NULL as a Literal Argument - 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)

Consider the following Extrapolate functions and the corresponding specific name as specified in the SPECIFIC clause of CREATE FUNCTION.

Function Name and Parameters Specific Name
Extrapolate(a INTEGER, b INTEGER, c INTEGER) S1
Extrapolate(a VARCHAR(20), b VARCHAR(20), c VARCHAR(20)) S2

The results of calling the function with NULL as a literal argument appears in the following table.

IF the function invocation is … THEN Teradata Database …
SELECT Extrapolate(3, NULL, 9);
invokes the function name with the specific name S1.
SELECT Extrapolate('Ver', NULL, '*.*');
invokes the function name with the specific name S2.
SELECT Extrapolate(NULL, NULL, NULL);
returns an error.
SELECT Extrapolate(CAST(NULL AS INTEGER), NULL, NULL);
invokes the function name with the specific name S1.