Behavior of Null Values in Commands and Functions
The following table describes how commands and functions interpret null values.
| Data type | Behavior |
|---|---|
Most logical expressions that evaluate to .NULL. return .NULL. or generate an error. EMPTY( ), ISBLANK( ), and ISNULL( ) are exceptions. |
|
Numeric expressions that evaluate to .NULL. return .NULL. A numeric function evaluates to .NULL. when passed a null value. |
|
Date expressions containing null values return .NULL. |
See Also
Reference
Null Value Handling
Date Data Type (Visual FoxPro)
EMPTY( ) Function
ISBLANK( ) Function
ISNULL( ) Function
Logical Data Type
Numeric Data Type
Behavior of Null Values in Logical Expressions