共找到 1348344 与那为何inlastterm 相关的结果,耗时2349 ms
设有关系R(A,B,C)和S(A,D,E,F),且R.A和S.A取自同一个域,与下面SQL语句: SELECT R.A,B,E,F FROM R,S WHERE R.A=S.A AND B=3等价的关系代数表达式是A.只有ⅠB.只有ⅡC.Ⅱ和ⅢD.都等价
设有关系R(A,B,C)和S(A,D,E,F),且R.A和S.A取自同一个域,与下面SQL语句; SELECT R.A,B,E,F FROM R,S WHERE R.A=S.A AND B=3 等价的关系代数表达式是______。Ⅰ.πA,B,E,F(σB=3(RS))Ⅱ.(πA,B(σB=3(R
A.(A, B, D, C, F, E, I, J, H, G)B.(A, B, D, C, E, F, I, H, G, J)C.(B, F, G, E, A, I, D, C, H, J)D.(B, F, G, J, A, E, D, I, C, H)
A.(B, F, G, J, A, E, D, I, C, H)B.(B, A, D, E, F, G, I, J, H, C)C.(A, B, D, C, E, F, I, J, G, H)D.(A, B, D, C, F, E, J, I, H, G)
A.(A, B, D, C, P, E, I, J, H, G)B.(A, B, D, C, E, F, I, H, G, J)C.(B, P, G, E, A, I, D, C, H, J)D.(B, F, G, J, A, E, D, I, C, H)
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