下面 语句和”select * from student where sex=’男’ && age=20;”语句查询出的结果是一样的。（ ） A: select * from student where sex=’男’ or age=20; B: select * from student where sex=’男’ || age=20; C: select * from student where sex=’男’ and age=20; D: select * from student where sex,age in(’男’,20);

查询年龄不在20到23岁之间的学生的信息，所使用的语法命令为（） A: select * from student where age not between 20 and 23 B: select * from student where age between 20 and 23 C: select * from student where age not between 20 to 23 D: select * from student where not age from 20 to 23

关系模式：Student（Sno, Sname, Age）,其中Sno、Sname、Age分别表示学生的学号、姓名和年龄。“查询年龄大于20岁的学生姓名”的关系代数表达式是（） A: σSname(σage>20(Student)) B: ΠSname(σage>20(Student)) C: σSname(Πage>20(Student)) D: ΠSno(σage>20(Student))

查询年龄在20到23岁之间的学生的信息，所使用的语法命令为（） A: select * from student where age between 20 to 23 B: select * from student where age from 20 to 23 C: select * from student where age between 20 and 23 D: select * from student

有学生信息表student，求年龄在20～22岁之间(含20岁和22岁)的学生姓名和年龄的SQL语句是：SELECT sname,age FROM student WHERE age（ ）。 A: >20 and age<22 B: BETWEEN 20 AND 22 C: >=20 and age<22 D: >20 and age<=22