17.05 - UNION and NULL - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL Data Manipulation Language

Advanced SQL Engine
Teradata Database
Release Number
Release Date
January 2021
Content Type
Programming Reference
Publication ID
English (United States)

When you specify an explicit NULL for any union operation, its data type is INTEGER. For an example, see Example: Effect of Explicit NULLs on Data Type of a UNION.

On the other hand, column data defined as NULL has neither value nor data type and evaluates like any other null in a scalar expression.