ACC: "Invalid Use of Null" Error Message with Val() Function (90722)
The information in this article applies to:
- Microsoft Access 1.0
- Microsoft Access 1.1
- Microsoft Access 2.0
- Microsoft Access for Windows 95 7.0
This article was previously published under Q90722
Moderate: Requires basic macro, coding, and interoperability skills.
SYMPTOMS
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.
| Modification Type: | Major | Last Reviewed: | 5/9/2003 |
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| Keywords: | kberrmsg kbprb kbProgramming KB90722 |
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