看来还没达到楼主要求。再努力一下：
Data bbb;
set aaa;y=scan(x,2, ".");
if y=" " then decimal=0;
else decimal=length(scan(x,2, "."));
drop y;
run;
Decimal 就是数据aaa 中变量x的小数点位数。


Proc sql ;
select max(decimal) into :MaxDecimal
from bbb;
quit;
%put the maximum decimal is %left(&MaxDecimal);


最后用%put 把宏变量MaxDecimal的值写到SAS log:

the maximum decimal is 4

谢谢各位！

data aaa;
        set aaa;
        num=length(strip(x))-length(strip(scan(x,1,".")))-1;
        if num<0 then num=0;
run;
proc sql noprint;
        select max(num) into:num from aaa;
quit;
%put &num.;

data aaa;
input x;
cards;
11
111
;
run;
dec的结果应该是0，结果出错哦！

length改成lengthn就好了