Example: Function Mapping Definition with Scalar Subquery (SSQ) Substitution - Teradata Vantage

The function mapping definition sessionize_fm specifies a scalar subquery for the TIMEOUT column value:

SELECT timeout FROM ssqtbl WHERE username='John'

If TIMEOUT is not specified during function processing, the column value is resolved by processing the scalar subquery.

CREATE FUNCTION MAPPING sessionize_fm FOR sessionize SERVER coprocessor
USING
InputTable IN TABLE,
ModelTable IN TABLE,
ClusterTable OUT TABLE,
TIMECOLUMN,
TIMEOUT(SELECT timeout FROM ssqtbl WHERE username='John'),
CLICKLAG,
EMITNULL;