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

Question

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

Answer 1

正确答案：A
解析：GRADE BETWEEN 60 AND 90等价于GRADE＞=60 AND GRADE=90。