17.10 - RESET WHEN Condition Rules - Advanced SQL Engine - Teradata Database

Teradata Vantageā„¢ - SQL Functions, Expressions, and Predicates

Advanced SQL Engine
Teradata Database
Release Number
July 2021
English (United States)
Last Update

The condition in the RESET WHEN clause is equivalent in scope to the condition in a QUALIFY clause with the additional constraint that nested ordered analytical functions cannot specify conditional partitioning.

The condition is applied to the rows in all designated window partitions to create sub-partitions within the particular window partitions.

The following rules apply for RESET WHEN conditions.

A RESET WHEN condition can contain the following:
  • Ordered analytical functions that do not include the RESET WHEN clause
  • Scalar subqueries
  • Aggregate operators
  • DEFAULT functions

    However, DEFAULT without an explicit column specification is valid only if it is specified as a standalone condition in the predicate. For more information, see Rules For Using a DEFAULT Function As Part of a RESET WHEN Condition.

A RESET WHEN condition cannot contain the following:
  • Ordered analytical functions that include the RESET WHEN clause
  • The SELECT statement
  • LOB columns
  • UDT expressions, including UDFs that return a UDT value

    However, a RESET WHEN condition can include an expression that contains UDTs as long as that expression returns a result that has a predefined data type.