If 3.23.22 gave (NULL != 1) = TRUE, that was a bug, because in SQL, (NULL != 1) is NULL.

This 3.23.26 change history item might be your culprit: "Fixed `<>' to work properly with `NULL'."



Mike Rykowski wrote:

I have a query:

select * from table where del != "1";

Let's assume that I have a record where del is null (del is a single
character field).

In version 3.23.22-beta I get the record returned with the above query,
in version 4.1.10a I get nothing returned.

Did something change between these versions or is this a bug?  I
couldn't find anything specific to this on the archives.