有关系S(SNO, SNAME, SAGE),C(CNO, CNAME),SC(SNO, CNO, GRADE)。其中SNO是学生号,SNAME是学生姓名,SAGE是学生年龄, C#是课程号,CNAME是课程名称。要查询选修“ACCESS”课的年龄不小于20的学生姓名,则SQL语句是: SELECTSNAME FROM S,C,SC WHERE子句。 这里的WHERE子句的内容是( )。
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A.S.SNO = SC.SNO and C.CNO = SC.CNO and SAGE=20 and CNAME=‘ACCESS’
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B. S.SNO = SC.SNO and C.CNO = SC.CNO and SAGE =20 and CNAME in ‘ACCESS’
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C. SAGE in=20 and CNAME in ‘ACCESS’
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D. SAGE=20 and CNAME=’ ACCESS’