count 好像不行，因为逻辑值为 0或1，count以后是总数
可以改为sum()函数，这样只累计那些条件成立的记录

sum不行，sum要求是数值变量，字符型的不行！

sum应该可以：

proc sql;
create table wanted as
select grou, sum(a='y') as a1, sum(b='y') as b1, sum(c='y') as c1
from tt
group by grou;
quit;

用data步也比较方便：

proc sort data=tt;
by grou;
run;

data wanted;
set tt;
by grou;
if first.grou then do;
   a1=0;b1=0;c1=0;
end;
if a='y' then a1+1;
if b='y' then b1+1;
if c='y' then c1+1;
if last.grou;
keep grou a1 b1 c1;
run;

sum可以，刚才我错了

恩，不过最近对sql着魔了！