很简单嘛 <!-- s:lol: --><img src="{SMILIES_PATH}/icon_lol.gif" alt=":lol:" title="Laughing" /><!-- s:lol: -->
data one;
input x$ y;
cards;
a 3
b 5
a 2
b 4
run;
proc sort data=one;
by x;
data two;
set one;
by x;
retain total 0;
if first.x then total=0;
total=total+y;
if last.x ;
run;
proc print data=two;
run