请教一个存储过程的写法？（100分）

[bluefk]

现在有表如下字段traindata
clusterid //类号
customerid //顾客号
trainid //训练号
churnflag //流失标志 0 流失，1 不流失
每个trainid对应多条记录
现在要统记每次训练（根据trainid）中，某一类（根据clusterid）的顾客总数customernum，和这类顾客的流失率churnrate（a类流失顾客数/a类顾客的总数）并写入表trainresult中,字段如下
clusterid
customernum //顾客数量
churnrate //流失率

希望那位高手给写一下，不胜感激！

[caiyunxia]

create PROCEDURE pro_test @clusterid int,@trainid int
as
insert into trainresult
select @clusterid,count(*),1.0*sum(case when churnflag=0 then 1 else 0 end)/count(*)
from traindata where clusterid =@clusterid and trainid=@trainid

[funboy88]

insert into trainresult (trainid,clusterid,customernum,churnrate) (select trainid,clusterid,count(customerid),sum(case churnflag when 0 then 1 else 0 end))/count(customerid) from traindata group by trainid, clusterid)

[愉快的登山者]

create PROCEDURE pro_test @clusterid int, @trainid int
as
insert into trainresult
select @clusterid, count(clusterid), 1 - sum(cast(churnflag as int))/count(clusterid)
from traindata where clusterid =@clusterid and trainid=@trainid

[shierre]

to tj_dns(愉快的登山者),
你这个1 - sum(cast(churnflag as int))会不会有问题？

[dlkfth]

来晚拉

[erigido]

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