part3.txt

来自「ssd7 Exercise1 练习1 答案」· 文本 代码 · 共 13 行

( 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.