How do I fix null is invalid?

[Guest]

It appears after I reach a certain amount of order entries running a report
of Orders by employess seems impossible. Null is Invalid appears. Help I
have rewritten the program 3 times!

 

[Ken Snell [MVP]]

The error suggests that your report is using a query that contains a
function where Null is an invalid argument. This usually occurs when a field
in the query's data source contains Null in a field and you're using that
field in a function that is in a calculated field's expression.

You don't tell us the query that you're using, so you'll need to review the
query and see if this looks like what you're doing. You likely can avoid the
error by using the Nz function around the field within the function so that
you replace the Null value with a different value.