分数大于其所在工作(job)分数的平均分的所有grade属性

/*1、并表
select 
    id,
    job,
    score
from grade
left join (select job,avg(score) avg from grade group by job) t
using(job)
where score>avg
order by id

2、where子查询
select t.id,t.job,t.score
from grade t
where score>(select avg(score) from grade t1
             where t.job=t1.job
             group by t1.job)
order by t.id

3、窗口函数:where语句需写在外层查询中，写在内层查询会报错。
*/
select t.id,t.job,t.score
from (
    select 
        *,
        avg(score) over(partition by job) avg
    from grade
    ) t
where t.score>t.avg
order by t.id