Borislav...

>What is the result of that query:

SELECT jet.last_name,jet.first_name,jet.ssn;
FROM jet;
LEFT JOIN Person ON jet.ssn == Person.Ssn;
WHERE Person.ssn IS NULL

The result is the same (i.e....it is WRONG).

>WAIT WINDOWS TRANSFORM(LEN(jet.ssn))+[   -   ]+TRANSFORM(LEN(Person.ssn))

C - C

>WAIT WINDOWS TYPE([jet.ssn])+[   -   ]+TYPE([Person.ssn])

11 - 11

Actually, I was finding this problem before when JOINING, and that is why I was trying to figure out using the sub-SELECT.