大神何在,赶紧帮我看下这条sql语句答:select deptno,job,avg(nvl(sal,0)) 平均工资,avg(nvl(comm,0)) 平均奖金,case when avg(nvl(comm,0))>300 then '奖金不错'when avg(nvl(comm,0)) between 100 and 300 then '奖金一般'when avg(nvl(comm,0))<100 then '基本没有奖金' end 奖金状况from emp group by deptno,job ...