snocno主键学生信息人才遴选
题号: b7MbR8、下面题基于学生-课程数据库中的三个基本表：学生信息表：s(sno, sname, sex, age, dept) 主键为sno课程信息表：c(cno, cname, teacher) 主键为cno学生选课信息表：sc(sno, cno, grade) 主键为(sno, cno)“从学生选课信息表中找出无成绩的学生信息”的SQL语句是（ ）
A、A.SELECT * FROM sc WHERE grade=NULL
B、B.SELECT * FROM sc WHERE grade IS ‘ ’
C、C.SELECT * FROM sc WHERE grade IS NULL
D、D.SELECT * FROM sc WHERE grade =‘ ’
B、B.SELECT * FROM sc WHERE grade IS ‘ ’
C、C.SELECT * FROM sc WHERE grade IS NULL
D、D.SELECT * FROM sc WHERE grade =‘ ’
相关题目
下面题基于学生-课程数据库中的三个基本表: 学生信息表:s(sno, sname, sex, age, dept) 主键为 sno 课程信息表:c(cno, cname, teacher) 主键为
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 =‘ ’
下面基于学生课程
已解答已经存在学生信息表：s(sno, sname, sex, age, dept) 主码为sno 课程信息表：c(cno, cname, teacher) 主码为cno 学生选课信息表：sc(sno, cno
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 =' '
snocno主码选课信息929考试题库
已解答学生选课信息表:sc(sno, cno, grade),主键为(sno, cno),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=‘ ’
D、SELECT * FROM sc WHERE grade IS NULL
学生选课信息sc
已解答学生选课信息表:sc(sno, cno, grade),主键为(sno, cno),从学生选课信息表中找出无成绩的元组的SQL语句是( ).(3.0分)
A、SELECT * FROM sc WHERE grade=NULL
B、SELECT * FROM sc WHERE grade IS " "
C、SELECT * FROM sc WHERE grade=‘ ’
D、SELECT * FROM sc WHERE grade IS NULL
学生选课信息sc
已解答