ACC: "Invalid Use of Null" Error Message with Val() Function

• Microsoft Access versions 1.0, 1.1, 2.0, 7.0

SYMPTOMS

Moderate: Requires basic macro, coding, and interoperability skills.

If you create a function that uses the Val() function to evaluate a field that contains a null value, you may receive the following error message:

Invalid Use of Null

RESOLUTION

Make sure that the Val() function does not attempt to evaluate a field that contains a null value. Or, if you are not sure, add error trapping to your code to trap for this scenario.

MORE INFORMATION

The Val() function is designed to return the numeric value of a string. When the Val() function attempts to return the numeric value of null, an expression evaluation error occurs. Null is a Variant subtype used to indicate that a data item contains no valid data. Because the Val() function requires valid data, it cannot evaluate a null value.

STATUS

This behavior is by design.

REFERENCES

For more information about the Val() function, search for "Val," and then "Val Function" using the Microsoft Access Help Index.

Keywords          : kberrmsg kbprg 
Version           : 1.0 1.10 2.0 7.0
Platform          : WINDOWS 
Issue type        : kbprb 

Last Reviewed: March 10, 1999