【SAS NOTES】update

类似merge，update可以对数据集进行更新，但源数据集需要对关键字进行排序。而且备用数据集的结构要同源数据集保持一致。

data mysas.mmsuserdec;
    infile 'E:\SAS\mysas\mmsuserdec.txt' dlm='09'x firstobs=2;
    input date $ city $ a b c d;
run;
data mysas.mmsuserdec_replace;
    infile 'E:\SAS\mysas\mmsuserdec_replace' dlm='09'x firstobs=2;
    input date $ city $ a b c d;
run;
data mysas.mmsuserdec;
    update mysas.mmsuserdec mysas.mmsuserdec_replace;
    by city;
run;
proc print data=mysas.mmsuserdec;
run;