set serveroutput on

DECLARE

cursor cemp is select to_char(hiredate,'yyyy') from emp ;

phiredate varchar2(8);

count80 number :=0;

count81 number:=0;

count82 number:=0;

count87 number:=0;

begin

open cemp;

loop

fetch cemp into phiredate;

exit when cemp%notfound;

if phiredate='' then count80:=count80+1;

elsif phiredate='' then count81:=count81+1;

elsif phiredate=''then count82:=count82+1;

else count87:=count87+1;

end if;

end loop;

close cemp;

dbms_output.put_line('总数据:'||(count80+count81+count82+count87));

dbms_output.put_line('1980:'||count80);

dbms_output.put_line('1981:'||count81);

dbms_output.put_line('1982:'||count82);

dbms_output.put_line('1987:'||count87);

end;

/