Example: Function Mapping with Scalar Subquery (SSQ) Substitution that Includes a System Variable - Teradata VantageCloud Lake

The function mapping definition sessionize_fm specifies a TIMEOUT parameter derived from a scalar subquery that includes the system variable USER.

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

SELECT timeout FROM ssqtbl WHERE username=USER

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=USER),
CLICKLAG,
EMITNULL;