sas宏(2)，运行中创建宏与使用宏，proc sql创建宏, scl中宏处理(暂缺)

options symbolgen pagesize=30;  
%let crsnum=3; 
data revenue;    
set sasuser.all end=final; 
where course_number=&crsnum;     
total+1;       
if paid=‘Y‘ then paidup+1;    
if final then do;     
    if paidup<total then do;    
        call symput(‘foot‘,‘Some Fees Are Unpaid‘);     /*symput函数能达到运行时给宏赋值的效果*/
        /*%let foot=Some Fees Are Unpaid; */ /*使用let不能达到想要的效果，let会被宏处理器先执行，优先于data步*/
    end;          
    else do;      
        call symput(‘foot‘,‘All Students Have Paid‘);   
        /*%let foot=All Students Have Paid;*/  
    end;    
end;   
run;

call symput(‘numpaid‘,trim(left(paidup))); 

data _null_;
set sasuser.courses;
call symput(course_code, trim(course_title));/*每一个observation中的两个变量分别对于宏值与宏变量*/
run;
%put _user_;

/*想要用lv2来得到res*/
data _null_;
%let lv1 = res;
%let lv2 = lv1;
%put &lv2; /*一个红触发器无须解释,结果为lv1*/
%put &&lv2; /*这个看上去有理，但是得出的结果还是lv1*/
%put &&&lv2;/*这个得出的结果为res*/
run;

data teachers;
set sasuser.register;
length Teacher $ 20;
teacher=symget(‘teach‘||left(course_number));
run;

/*在行数位置的情况下创建多个宏变量*/
proc sql noprint;
    select count(*) into :numrows
        from sasuser.schedule
        where year(begin_date)=2002;
%let numrows=&numrows; /*消除首尾空白*/
%put There are &numrows courses in 2002;
    select course_code, location,
            begin_date format=mmddyy10.
        into :crsid1-:crsid&numrows,
             :place1-:place&numrows,
             :date1-:date&numrows
        from sasuser.schedule
        where year(begin_date)=2002
        order by begin_date;
%put _user_;
quit;

proc sql noprint;
    select distinct location into :sites separated by ‘ ‘
        from sasuser.schedule;
quit;