with t as (
select id,sum(cs) sumcs,count(cs) countcs from b group by id
)
select a.id,a.n,t.sumcs,t.countcs
from t join a on a.id=t.id
--这样最快吧
select id,sum(cs) sumcs,count(cs) countcs from b group by id
)
select a.id,a.n,t.sumcs,t.countcs
from t join a on a.id=t.id
--这样最快吧
解决方案 »
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