I think this might boil down to one's concept of what the Where clause is and what it does - at least it has become that IMHO. By definition, it specifies criteria that field values must meet for the records that contain the values to be included in the query results. If an expression evaluates to true or false and true or false is what the field contains, it ought to work if you pass the result as criteria regardless of whether or not it returns the expected records. If the expression evaluates to true or false and the field does not contain true or false values, I'd expect it to not return records and perhaps raise a data type mismatch error. If the expression returns Null and you pass =Null to the criteria clause, you will raise the error I already mentioned. If you pass 'Null' (without the quotes) Access query def will convert it to Is Null as I said. I don't know if it will do that in the case of vba generated sql but I'm not inclined to test it as it would just be a factoid about something that we should never be dealing with anyway. By that I mean if one has an inherent understanding of the basics of Null in terms of sql, you ought to be doing everything to prevent it or convert it unless you are specifically looking for records where the field has no values and does not hold an empty string.
So I do agree with Isladogs re semantics, assuming we agree on the basics about Null.
