sql script
select g.id, g.job, g.score
from (select job, avg(score) as avg_score
from grade
group by job) tmp, grade g
where tmp.job=g.job
and g.score > tmp.avg_score 
select g.id, g.job, g.score
from (select job, avg(score) as avg_score
from grade
group by job) tmp, grade g
where tmp.job=g.job
and g.score > tmp.avg_score