data test3;
merge test1 test2;
by SOC_TXT PT_TXT AEVGRD1C;
run;
等价于 full join
data test3;
merge test1(in=a) test2(in=b);
by SOC_TXT PT_TXT AEVGRD1C;
if a;
run; 等价于 left join
data test3;
merge test1(in=a) test2(in=b);
by SOC_TXT PT_TXT AEVGRD1C;
if a and b;
run; 等价于 inner join