数据库试题

WHERE SN=’王二’=’化学’РB. UPDATE S SET grade=’85’ WHERE SN=’王二’=’化学’РC. UPDATE grade=85 WHERE SN=’王二’=’化学’РD. UPDATE grade=’85’ WHERE SN=’王二’=’化学’Р37.设A.B两个表的记录数分别为3和4,对两个表执行交叉联接查询,查询结果中最多可获得( C )条记录。РA. 3 B. 4 C. 12 D. 81Р38.关于查询语句的SELECT子句为SELECT A,B,C *D,则不能使用的GROUP B子句是( D )РA.GROUP BY A B.GROUP BY A,B РC. GROUP BY A,B,C *D D. GROUP BY A,B,C D Р39.查询每门课程的最高分,要求得到的信息包括课程名称和分数,正确的命令是(B )РA. SELECT 课程名称,SUM(分数)AS分数РFROM curriculum, gradeРWHERE curriculum. 课程编号= grade.课程编号РGROUP BY课程名称РB. SELECT 课程名称,MAX(分数)分数РFROM curriculum, gradeРWHERE curriculum. 课程编号= grade.课程编号РGROUP BY课程名称РC. SELECT 课程名称,SUM(分数)分数РFROM curriculum, gradeРWHERE curriculum. 课程编号= grade.课程编号РGROUP BY curriculum.课程名称РD. SELECT 课程名称,MAX(分数)AS分数РFROM curriculum, gradeРWHERE curriculum. 课程编号= grade.课程编号РGROUP BY curriculum.课程名称