身份证的第7-14位是出生年月日。以身份证号442423199102280873为例：
data aa;
input x $ 7-14;
y=input(x,yymmdd10.);
age=intck('year',y,date());
cards;
442423199102280873
;
run;
得到的age变量就是年龄。

data pieces_parts;
input id $ 1-18;
length num $ 4;
num = 2015-input(substr(id,7,4),4.);
datalines;
432926197605200014
;
title "Listing of Data Set PIECES_PARTS";
proc print data= pieces_parts noobs;
run;