sas call sortc 函数

data a;
input x$ y$ @@;
cards;
a b
c d
b a
d c
a b ;
data b;
set a;
call sortc(x,y);
proc sort data = b out = c nodupkey;
by x y;
/*proc sql;
create table c
as select distinct x,y from b;
quit;*/
proc print; run;

/*data b;set a;if x > y then z = x||y;else z = y ||x;run;proc sort data = b out = c nodupkey;by z;proc print;run;*/