data a;
input State $ Note $;
cards;
CA A
CA B
CA C
CA D
DE A
DE R
DE I
DE W
PA W
PA E
PA W
;
run;
proc sort data=a;
by state note;
run;
data b;
length agg $ 50;
set a;
by state note;
retain agg;
if first.state then agg=note;
else agg=agg||note;
run;
我以为出来的结果会类似:
CA A A
CA B AB
CA C ABC
CA D ABCD
DE A ...
DE R
DE I
DE W
PA W
PA E
PA W
可是出来的却是:
CA A A
CA B A
CA C A
CA D A
DE A ...
DE R
DE I
DE W
PA W
PA E
PA W
请问,这个问题出在哪里呢???