SQL script to compare what is NOT IN...

SELECT COUNT(*)

FROM dbo.ssFields

WHERE field7='legal'

AND  ArchiveID =  '1' --Travel Agency

AND (Field1) NOT IN(

       SELECT (Field1) AS CompareString

       FROM dbo.ssFields

       WHERE field7='legal'

       AND  ArchiveID =  '8' --Travel Agency - Date Fix

)