数据库 关系代数小问题
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发布时间：2022-05-03 05:39
共1个回答
热心网友
时间：2023-10-11 12:13
2.select SN from S where SNO in (select SNO from SC where ENO in ( select ENO from T where EN="王平" ) )
3.select SN from S where SNO not in (select SNO from SC,T where SC.ENO=T.ENO and DEPT="信息系")
热心网友
时间：2023-10-11 12:13
2.select SN from S where SNO in (select SNO from SC where ENO in ( select ENO from T where EN="王平" ) )
3.select SN from S where SNO not in (select SNO from SC,T where SC.ENO=T.ENO and DEPT="信息系")
