data z1;
put _ALL_;
set sashelp.class;
put _ALL_;
weight2=weight/2;
put _ALL_;
run;

*kolumny zliczeniowe,wartosc aut;
data z2;
set sashelp.cars;
 *retain total 0; /*retain nazwa wartość*/
*total = total + invoice;

total + invoice;

if koniec then output;
keep total;
run;

*przetwarzanie w grupach ;

proc sort data = sashelp.cars out=cars;
data z3;
set sashelp.cars;
by make; /* przetwarzanie w grupach */
*col1=first.make;
*col2=last.make;

if first.make  then do;
licznik =0;
suma =0;
end;
licznik +1;
suma+invoice;
if last.make then output;
keep make licznik suma;
run;

*sashelp.air;
 data z4;
 set sashelp.air;
 rok=year(date);
 run;

 data z5;
 set z4;
 by rok;

if first.rok then suma =0;
suma +air;
if last.rok;
keep rok suma;

 run;
 *podaj 3 najdrozsze auta dla kazdej marki;

 proc sort data = sashelp.cars
 out=cars;
 by make descending invoice;
 run;

 data z6;
 set cars z6;
 by make;
 if first.make then licznik =0;
 licznik +1;
 if licznik <=3 then out = cars;
 run;



proc sort data = sashelp.class;
 out=class;
 by make descending invoice;
 run;

 data z7;
 set class z7;
 by height;
 if first.height then output max;

 if last.height then output = min;
 run;