如何用SQL语句选出两个表的不同记录！

Question

select * from tblA A where not exist
(select * from  tblB B where A.FIELDNAME=B.FIELDNAME)

Answer 1

SELECT * FROM Table2 WHERE Table2.AFiled NOT IN (
  SELECT AField FROM Table1
)

Answer 2

select PrimaryA, ForeignKey, ... from TableA 
where ForeignKey not in
(select PrimaryKeyB from TableB)
TableA                               TableBPrimaryA  (PK)
ForeignKey (FK)----> PrimaryKeyB (PK)