SQL语句中删除视图的命令是( )。

A．SELECT学号FROM score sc WHERE课程号="Cl"AND学号IN <br/> 　　(SELECT学号FROM score sc WHERE课程号="C5")
B．SELECT学号FROM score sc WHERE课程号="Cl"AND学号= <br/> 　　(SELECT学号FROM score sc WHERE课程号="C5")
C．SELECT学号FROM score sc WHERE课程号="Cl"AND课程号="C5"
D．SELECT学号FROM score sc WHERE课程号="Cl"OR课题号="C5"

A．SELECT S．学号，姓名，平均成绩FROM student s，score sc
　　WHERE S．学号=sc．学号
　　GROUP BY s．学号HAVING COUNT(*)>=5 ORDER BY平均成绩DESC
B．SELECT s．学号，姓名，AVG(成绩)FROM student s，score sc
　　WHERE s．学号=S
C．学号AND COUNT(*)>=5
　　GRoUP BY学号0RDER BY 3 DESC C．SELECT S．学号，姓名，AVG(成绩)平均成绩FROM student s，score sc
　　WHERE s．学号=S C．学号AND COUNT(*)>=5
　　GROUP BY s．学号ORDER BY平均成绩DESC
D．SELECT s．学号，姓名，AVG(成绩)平均成绩FROM student s，score sc
　　WHERE s．学号=sc．学号
　　GROUP BY s．学号HAVING COUNT(*)>=5 0RDER BY 3 DESC