AVERAGE

proc sort data=sashelp.class out=avgd;
by sex;
run;

proc sql;
create table avg  as select avg(age)as avrg, sex from sashelp.class
group by sex;
quit;
data bb;
SET AVGD avg;
BY SEX;
if missing (age)THEN DO
SEX= ""  ;
age=avrg;
END;
DROP AVRG;
run;

average

data base;
input id visit$ aval;
cards;
101 scr  20
101 base 25
101 v1   25
101 v2   26
102 scr  25
102 base 30
102 v1   25
102 v2   30
103 scr  23
103 base 33
;
run;

create seq
data gg;
set base;
by id;
if first.id=1 then seq=1;
else seq+1;
run;


data ds avg1;
set gg;
by id;
if seq > 2 then output avg1;
else output ds;
run;

proc sql;
create table dos as select avg(aval) as avg,id from avg1
group by id;
quit;
data final;
set ds avg1 dos;
by id;
if missing (aval) then aval=avg;
/*drop seq avg;*/
run;