part3.txt

来自「ssd7 exercise 1 ,绝对有用~欢迎下载」· 文本 代码 · 共 23 行

1.
s-r:

D | E | F
---------
b | g | a 


2.
( 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'
);

Returns a list of member numbers of all members currently borrowing the book that has only call number QA76.9.D26C66 but not call number QA76.9.D7E53.