基于"学生-选课-课程"数据库中的三个关系:
S(S#,SNAME,SEX,BIRTHYEAR,DEPT),主码为S#
C(C#,CNAME,TEACHER),主码为C#
SC(S#,C#,GRADE),主码为(S#,C#)
查找"由王建老师执教的操作系统课程的平均成绩、最高成绩和最低成绩",正确的SQL语句是
- A.SELECT AVG(GRADE), MAX(GRADE), MIN(GRADE) FROM C, SC GROUP BY CNAME = "操作系统" AND TEACHER = "王建"
- B.SELECT AVG(GRADE), MAX(GRADE), MIN(GRADE) FROM C, SC WHERE CNAME = "操作系统" AND TEACHER = "王建" AND SC.C# = C.C#
- C.SELECT AVG(GRADE), MAX(GRADE), MIN(GRADE) FROM C, SC HAVING CNAME = "操作系统" AND TEACHER = "王建" AND SC.C# = C.C#
- D.SELECT AVG(GRADE), MAX(GRADE), MIN(GRADE) FROM C, SC HAVING CNAME = "操作系统" AND TEACHER = "王建"
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1GB的准确值是( )。
有以下程序
#include
void f(int b[])
{ int i;
for (i=2; i<6; i++) b[i] *= 2;
}
main()
{ int a[10]={1,2,3,4,5,6,7,8,9,10}, i;
f(a);
for (i=0; i<10; i++) printf("%d,", a[i]);
}
程序运行后的输出结果是
以下ARM指令中源操作数属于立即寻址的指令是( )。