options pageno=1 nodate linesize=80 pagesize=60; 

data salaries;   

input Department $ Name $ WageCategory $ WageRate;   

datalines;

BAD Carol Salaried 20000

BAD Elizabeth Salaried 5000

BAD Linda Salaried 7000

BAD Thomas Salaried 9000

BAD Lynne Hourly 230

DDG Jason Hourly 200

DDG Paul Salaried 4000

PPD Kevin Salaried 5500

PPD Amber Hourly 150

PPD Tina Salaried 13000

STD Helen Hourly 200

STD Jim Salaried 8000

;

proc print data=salaries;

run;

proc sort data=salaries out=temp;   

by Department;

run;

data budget (keep=Department Payroll);  

set temp;      

by Department;

if WageCategory='Salaried' then YearlyWage=WageRate*12;   

else if WageCategory='Hourly' then YearlyWage=WageRate*2000;  

if first.Department then Payroll=0;   

Payroll+YearlyWage;

if last.Department;

run;

proc print data=budget;   

format Payroll dollar10.;

title 'Annual Payroll by Department';

run;

Output from Conditional BY-Group Processing

                        Annual Payroll by Department              

                        Obs    Department       Payroll

                         1        BAD          $952,000

                         2        DDG          $448,000

                         3        PPD          $522,000

                         4        STD          $496,000

二、数据不是按照字母或者数字排序

   在进行BY-Group处理操作时，不仅可以利用按照字母或者数字排序的数据，还可以按照日历月份或者分类等排列的数据。只需要在你使用SET语句时，在By语句后面加个Notsorted选项即可。Notsorted选项的作用就是告诉SAS数据不是按照字母或者数字大小排序的，而是按照By变量的值按组排列的。

     Notsorted选项不能用在Merge语句、Upgrade语句，或者当SET语句后多于一个数据集的时候。

       下面的例子假定数据是按照字符变量Month分组的，IF语句根据Last.Month的值有条件的写记录到数据集。数据步只会在每个By组处理完后写记录到数据集。

data total_sale(drop=sales); 

set region.sales

by month notsorted;    

total+sales;    

if last.month; 

run;