假定学生关系是S(SNo,SName,Sex,Age),课程关系是c(CNo,CName,Teacher),学生选课关系是SC(SNo,CNo,Grade)。要查找选修数据库课程的男学生姓名,将涉及的关系是()。
A,SC
B、s
C、S,SC,C
D、SC,C
A,SC
B、s
C、S,SC,C
D、SC,C
A、SELECT S#,SUM(GRADE) as Sgrade FROM SC WHERE GRADE>=60 GROUP BY S# HAVING COUNT(*)>=4 ORDER BY Sgrade DESC
B、SELECT S#,SUM(GRADE) as Sgrade FROM SC WHERE GRADE>=60 GROUP BY S# HAVING COUNT(*)>=4 ORDER BY Sgrade
C、SELECT S#,SUM(GRADE) as Sgrade FROM SC WHERE GRADE>=60 HAVING COUNT(*)>=4 GROUP BY S# ORDER BY Sgrade DESC
D、SELECT S#,SUM(GRADE) as Sgrade FROM SC WHERE GRADE>=60 and COUNT(*)>=4 GROUP BY S# ORDER BY Sgrade DESC
A、其他都不对
B、
C、
D、
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