A、select sno,avg(score) as sscore from sc group by sno having avg(score) >60
B、select sno,avg(score) as sscore from sc group by sno where avg(score) >60
C、select sno,avg(score) as sscore from sc where avg(score) >60
D、select sno,avg(score) as sscore from sc having avg(score) >60
A、SELECT Sno, AVG(Grade) FROM SC GROUP BY Sno HAVING AVG(Grade)>=60;
B、SELECT Sno FROM SC WHERE Grade>=60 GROUP BY Sno;
C、SELECT Sno, Grade FROM SC GROUP BY Sno HAVING AVG(Grade)>=60;
D、SELECT Sno FROM SC GROUP BY Sno HAVING Grade >=60;
从学生选课信息表中找出无成绩的元组的SQL语句是()。
A.SELECT*FROM sc WHERE grade=NULL
B.SELECT*FROM sc WHERE grade IS"
C.SELECT*FROM sc WHERE grade IS NULL
D.SELECT*FROM sc WHERE grade="
A.为表“选课”中成绩小于60分的记录做删除标记
B.从表“选课”中彻底删除成绩小于60分的记录
C.删除“选课”表
D.删除“选课”表的年龄属性
第下列各题基于学生表s和学生选课表SC两个数据库表,它们的结构如下: s(学号,姓名,性别,年龄),其中学号、姓名和性别为C型字段,年龄为N型字段。 SC(学号,课程号,成绩),其中学号和课程号为C型字段,成绩为N型字段(初始为空值)。 查询学生选修课程成绩小于60分的学号,正确的SQL语句是()。
A.SELECT DISTINCT学号FROM SC WHERE”成绩”<60
B.SELECT DISTINCT学号FROM SC WHERE成绩 <”60”
C.SELECT DISTINCT学号FROM SC WHERE成绩 <6。
D.SELECT DISTINCT”学号”FROM SC WttERE”成绩”<60
回答下列各题: 基于学生表S和学生选课表SC两个数据库表,它们的结构如下: S(学号,姓名,性别,年龄),其中学号、姓名和性别为C型字段,年龄为N型字段。 SC(学号,课程号,成绩),其中学号和课程号为C型字段,成绩为N型字段(初始为空值)。 查询学生选修课程成绩小于60分的学号,正确的SQL语句是()。
A.SELECT DISTINCT学号FROM SC WHERE"成绩"<60
B.SELECT DISTINCT学号FROM SC WHERE成绩<"60"
C.SELECT DISTINCT学号FROM SC WHERE成绩%60
D.SELECT DISTINCT"学号"FROM SC WHERE"成绩"<60
A.SELECT * FROM sc WHERE grade=NULL
B.SELECT * FROM sc WHERE grade IS ' '
C.SELECT * FROM sc WHERE grade IS NULL
D.SELECT * FROM sc WHERE grade =' '
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