Yuri, thanks for the response.

It is still not clear for me:

1) select * from vehicles_t where vehicle_code = .null.
can be executed with no errors

2) VFP help says - "Visual FoxPro support for null values complies with ANSI standards".
The SQL-92 standard requires that an equals (=) or not equal to (<>) comparison against a null value evaluates to FALSE.

From my point it means
select * from vehicles_t where vehicle_id = .null.
shouldn't raise any error and empty recordset should be returned

Thank you