SAS合并多个表 [英] SAS merging multiple tables

问题描述

我想知道合并多个表的最佳方法是什么.我在所有表中都有一个唯一标识符.我应该在对表格进行排序后一步加入所有表格，还是应该逐一合并表格.这有关系吗?

I would like to know what is the best way to merge multiple tables. I have a unique identifiers across all the tables. Should I join all the tables in one step after sorting the tables OR should I should do stepwise one by one table merging. Does this matter ?

推荐答案

您可以在一个步骤中进行多个合并.然而，这并不是最安全的方式.如果您的数据可能存在缺陷，最好逐步执行此操作.恕我直言，最好在当时合并一个步骤，但这是你的决定.

You can do multiple merges at single step. However, this is not the safest way. If there is possibility that your data is subject to imperfections, it is best to do this step by step. Imho, it is best do merge a step at the time, but it's your call.

proc sort data=data1; by id; run;
proc sort data=data2; by id; run;
proc sort data=data3; by id; run;

data combo;
    merge data1(in=a) data2(in=b) data3(in=c); 
    by id; 
    if a and b and c; /*Inner join. Change as needed. */
run;

这相当于:

data partial;
    merge data1(in=a) data2(in=b);
    by id; 
    if a and b; 
run;

data combo;
    merge partial(in=a) data3(in=b);
    by id; 
    if a and b;
run,

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