按照学生平均成绩(avg_grade) 将students表中的数据检索出来,下面SQL语句正确的是( )
A) SELECT * FROM students ORDER BY avg_grade
B) SELECT * FROM students GROUP BY avg_grade ASC
C) SELECT * FROM students ORDER BY avg_grade DESC
D) SELECT * FROM students ORDER by avg_grade asc
给出答案是AD,也有说C也没错,究竟怎么说??
參考答案:A:ORDER BY 默认升序排列
D:ORDER BY asc 升序排列
C:ORDER BY desc降序排列