part3.txt

ssd7数据库系统练习一

s-r

A B C 
b g a

( SELECT   MemNo
  FROM     MEMBER, BOOK
  WHERE    MemNo = BorrowerMemNo AND
  CallNumber = 'QA76.9.D26C66'
)
EXCEPT
( SELECT   MemNo
  FROM     MEMBER, BOOK
  WHERE    MemNo = BorrowerMemNo AND
  CallNumber = 'QA76.9.D7E53'
);

The above statement  returns a list of member numbers of the members only borrowing the book that has the call number QA76.9.D26C66 but not borrowing the book that has the call number QA76.9.D7E53.