更多"A) from C) with B) in "的相关试题:
[单项选择][A] among [C] in
[B] between [D] to
A. among
B. between
C. in
D. to
[单项选择]A) for C) of
B) from D) with
A. for
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[单项选择][A] across [C] from
[B] to [D] through
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[单项选择]设有关系R(A，B，C)和S(C，D)与SQL语句SELECT A，B，D FROM R，S WHERE R.C=S．C等价的关系代数表达式是( )。
A. σ
B. πA，B，D(σ
C. σ
D. σ
[单项选择]设有关系R(A，B，C) 和S(C，D) ：与SQL语句SELECTA，B，D FROM R，S WHERER，c=S．c等价的关系代数表达式是( )。
A. R，C=
B. B．
C. D(
D. S．C((BR)×(DS))
E. R．C=S，C(D((BR)×S))
[单项选择]设有关系R(A,B,C) 和S(C,D) 。与SQL语句select A,B,D from R,S where R.C=S.C等价的关系代数表达式是______。
A. σC=C(πA,B,D(R×)
B. πA,B,D(σC=C(R×)
C. σC=C((πA,B×(πD)
D. σC=C(πD(πA,B×
[单项选择]设有关系R(A，B，C)和S(C，D) 与SQL语句SELECT A，B，D FROM R，S WHERE R.C=S.C等价的关系代数表达式是
A. σC=C(πA，B，D(R×)
B. πA，B，D(σC=C(R×)
C. σC=C((πA,B×(πD)
D. σC=C(πD((πB×
