窗体顶端1.根据SQL标准，要修改表student中所有学生的年龄age，使之在原值基础上减一，下面哪个语句适用？A update student set age = 1B update student set age = age - 1C update age = age -1 from student D update from student where age = age -1 正确答案:B 2.根据SQL标准，要查询表student中所有年龄age小于所有学生的平均年龄的记录，下面哪条语句适用？A select * from student where age avg(age)B select * from student having age avg(age)C select * from student a where a.age (select avg(b.age) from student b)D select * from student a where (select avg(b.age) from st
