MERGE语句——数据集横向合并

一.运用By语句

proc sort data=data-set1 out=data-set2；

by var1;

run;

proc sort data=data-set3 out=data-set4;

by var1;

run;

data data-set5;

merge data-set2 data-set3;

by var1;

run;

（二）SQL（join,left join,right join,full join） [join相当于交集；merge相当于full join,并集]

proc sql;

select * from dataset1 left join dataset2

on dataset1.id=dataset2.id;

quit;