关于Oracl语句分组问题

Question

select loc ,max(deptno) from dept group by loc order by deptno语句报错
既然max是分组函数，为什么不能对deptno进行排序呢。

Answer 1

select loc ,max(deptno) as deptno from dept group by loc order by deptno 这样就可以了