In Chapter 8 page 241 it discusses creating a optional query parameter by adding a OR [para] IS NULL to the criteria. I created a example that works fine when I pass it a regular value. But when trying to pass it the NULL I just get a “Sorry, a server error has occurred” message.

Here is what I did to try this:
Created a query of my data with a parameter and used it in the criteria like “[pOrg] OR [pOrg] IS NULL”. When saved and then Designed View’ed again Access has created a column for the [pOrg] with criteria IS NULL and used the [pOrg] under my column as a Equals criteria. Just like the example in the book.

I created a DataSheet View based on the query.

On a form I added a TextBox for the filter value and a Button to open up the datasheet view as a popup. In the button macro I test the TextBox for a null or value and do a SetVariable called gTxtFilter to either NULL or the text box value. In a OpenPopup I selected my datasheet view and set the parameter to gTxtFilter.

What am I doing wrong?

PS: I have some screen shots of this, but see no way to post them.

Just to be 100% sure we set the criteria correctly, enter the criteria as this way:

When you save the query and open it, it will look a bit different because as explained in the book (pg. 244-246), Access query designer changes the expression into two columns. For multiple parameters, it could be daunting and thus, keeping the original criteria in a notepad is probably good idea when you need to edit the query.