可是，当我加入时间变量，加入求的是每天的行业收益率。小弟修改代码如下：
data a;
input n r sic value date ddmmyy8.;
format date ddmmyy10.;
cards;
1  0.1  1   109 01-12-10
2  0.2  1   209 01-12-10
3  0.3  1   167 01-12-10
4  0.1  2   123 01-12-10
5  0.2  2   200 01-12-10
6  0.3  2   210 01-12-10
7  0.4  2   342 02-12-10
8  0.12 1   223 02-12-10
1  0.29 1   560 02-12-10
;
proc sql;
create table result as
select distinct  a.n,a.r,a.sic,sum(b.value*b.r)/sum(b.value) as weight label='weighted return' format=7.2 from
a join  a b
on a.sic=b.sic and
a.n ne b.n and a.date= b.date
group by a.n and a.date
order by a.n;
quit;
（为啥运行结果就是不对的呢？？）盼望指教啊

顶起啊~~！！高手解答！

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顶起啊