求助sas 多表合并问题

data a1;
input bh1 sz1;
cards;
5 13
7 12
;

run;
data a2;
input bh2 sz2;
cards;
5 14
7 23
;

run;
data a3;
input bh3 sz3;
cards;
18 14
7 23
;

run;
proc sort data=a1 ;by bh1;run;
proc sort data=a2 ;by bh2;run;
proc sort data=a3 ;by bh3;run;
/*变量bh1 bh2 bh3 改名为bh 好合并*/
data a_1;
set a1(rename=(bh1=bh));
run;
data a_2;
set a2(rename=(bh2=bh));
run;
data a_3;
set a3(rename=(bh3=bh));
run;
data cc;
merge a_1 a_2 a_3;
by bh;
run;

和上面 Imasasor 用宏是一个意思...(核心就是rename bh（i）变量 为bh)

BH列的数值不唯一（两个56），用merge by 没问题吗？