对于基本表S(S,Name,Sex,Birthday)和SC(S,C,Grade),其中S、Name、Sex、Birthday、C和G rade分别表示学号、姓名、性别、生日、课程号和成绩。与下列SQL语句等价的关系代数式是______。 SELECT S,Name FROM S WHERE S NOT IN (SELECT S FROM SC WHERE C='c102')。

A.πS,Name(σC≠'c102'(S<img src='https://img2.soutiyun.com/ask/uploadfile/1341001-1344000/323a4ae71591ced9c23849d07bd3a76b.jpg' />SC)) B.πS,Name(S)-πS,Name(σC≠'c102'(S<img src='https://img2.soutiyun.com/ask/uploadfile/1341001-1344000/323a4ae71591ced9c23849d07bd3a76b.jpg' />SC)) C.πS,Nmne(S<img src='https://img2.soutiyun.com/ask/uploadfile/1341001-1344000/323a4ae71591ced9c23849d07bd3a76b.jpg' />σC≠'c102'(SC)) D.πS,Name(S<img src='https://img2.soutiyun.com/ask/uploadfile/1341001-1344000/3fc30a9ef68a99730b1bdc9d3e7b5749.jpg' />(SC))

时间:2023-03-17 14:17:51

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