(31)到(35)题使用下列数据表。
“学生”表:学号C(8),姓名C(8),性别C(2),系名(10),出生日期D
“课程”表:课程编号C(4),课程名称C(12),开课系名C(10)
“成绩”表:学号C(8),课程编号C(4),成绩I
检索每门课程的总分,查询结果中包括课程名和总分,正确的命令是( )。
A.SELECT 课程名称,COUNT(成绩) AS 总分 FROM 课程,成绩;
WHERE 课程.课程编号=成绩.课程编号;
ORDER BY 成绩.课程编号
B.SELECT 课程名称,COUNT(成绩) AS 总分 FROM 课程,成绩;
WHERE 课程.课程编号=成绩.课程编号;
GROUP BY 成绩.课程编号
C.SELECT 课程名称,SUM(成绩) AS 总分 FROM 课程,成绩;
WHERE 课程.课程编号=成绩.课程编号;
ORDER BY 成绩.课程编号
D.SELECT 课程名称,SUM(成绩) AS 总分 FROM 课程,成绩;
WHERE 课程.课程编号=成绩.课程编号;
GROUP BY 成绩.课程编号