在关系SC中,查询学习课程号为′DB′,且成绩在60至90之间的学生学号的正确的 SQL命令是A.SELECT SNO
在关系SC中,查询学习课程号为′DB′,且成绩在60至90之间的学生学号的正确的 SQL命令是
A.SELECT SNO FROM SC WHERE CNO=′DB′AND GRADE DETWEEN 60 AND 90
B.SELECT SNO FROM SC WHERE CNO=′DB′OR GRADE BETWEEN 60 AND 90
C.SELECT SNO FROM SC WHERE CNO=′DB′AND GRADE>=60 AND 90
D.SELECT SNO FROM SC WHERE CNO=′DB′AND GRADE<=60 AND GRADE>=90