Behavior of Null Values in Commands and Functions

The following table describes how commands and functions interpret null values.

Data type	Behavior
Logical	Most logical expressions that evaluate to .NULL. return .NULL. or generate an error. EMPTY( ), ISBLANK( ), and ISNULL( ) are exceptions.
Numeric	Numeric expressions that evaluate to .NULL. return .NULL. A numeric function evaluates to .NULL. when passed a null value.
Date	Date expressions containing null values return .NULL.

See Also