Invalid use of Null explained

[Claude]

Could one of you clever pros kindly try to point me in the right direction;
When creating a query, I get the error message "Invalid use of Null". I have
used the Nz function in all the calculations, to no avail. If I could know
why this error is generated, I might be able to find the bugger causing it.
Thanks. Claude

 

[kingston via AccessMonster.com]

Make a copy of the query and drop fields from your query one by one to
pinpoint the problem. If this doesn't work, then it is in your relationships.
You might be trying to join on a datapoint that is Null. You can fix this by
going into SQL mode and using Nz([ProblemField],...).

 

[John W. Vinson]

Could one of you clever pros kindly try to point me in the right direction;
When creating a query, I get the error message "Invalid use of Null". I have
used the Nz function in all the calculations, to no avail. If I could know
why this error is generated, I might be able to find the bugger causing it.
Thanks. Claude

You'll get this error if you try to assign a NULL value to a Number or String
datatype (either in an assignment statement or in a function call). Only a
Variant datatype variable can be set to NULL.

Are you calling any functions or doing any math operations in the query?
Perhaps you could post the SQL here.

John W. Vinson [MVP]