设有学生关系S(Sno, Sname, Sage),课程关系C(Cno, Cname),选修关系SC(Sno, Cno, Grade),其中Sno是学号,Sname是学生姓名,Sage是学生年龄,Cno是课程号,Cname是课程名,Grade是成绩。要查询选修了“ACCESS”课程的年龄不小于20的全体学生姓名,可用SELECT SNAME FROM S, C, SC WHERE 语句实现。
选项:
A:S.Sno=S
C:Sno and
C:Cno=S
C:Cno and Sage >=20 and Cname = ‘ACCESS‘;
B:S.Sno=S
C:Sno and
C:Cno=S
C:Cno and Sage in >=20 and Cname in ‘ACCESS‘;
C:Sage in >=20 and Cname in ‘ACCESS‘;
D:Sage in >=20 and Cname = ‘ACCESS‘
发布时间:2024-05-07 19:26:40