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Visual FoxPro provides support for null values. This support simplifies the task of representing unknown data and makes it easier to work with Microsoft Access or SQL databases that may contain null values.

Null values are:

Null values affect the behavior of commands and functions, logical expressions, and parameters.

Visual FoxPro support for null values complies with ANSI standards and affects any area of the product where values and expressions are used.

To use null values in See

Commands and functions

Behavior of Null Values in Commands and Functions


Behavior of Null Values in Logical Expressions


NULL as a Parameter

Using NULL in Values and Expressions

In Visual FoxPro, you assign the null value programmatically with the .NULL. token or interactively with CTRL+0 in a field. Note that the periods around .NULL. are optional. To detect whether a field or variable contains a null value, or whether an expression evaluates to a null value, use ISNULL(В ).

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