题解 | 查询成绩

# with t1 as(
#     select
#     a.sId,
#     b.cId,
#     c.cname,
#     b.score
# from Student as a
# left join SC as b on a.sId=b.sId
# left join Course c on b.cId=c.cId
# )
# select
#     count(*)
# from(

# select
#     t1.sId,
#     avg(t1.score) as avg_score
# from t1
# group by t1.sId
# having avg_score > 60
    
# ) t2
select
    count(*)
from(
select
    sId
from SC
group by sId
having avg(score) >60   
) a