PL/SQL 循环 if判断

declare
   i varchar2(10) := '张三';          
begin
  dbms_output.put_line(i);
end;
declare
 i emp.sal%type;
 begin
    select sal into i from emp where empno = 7369;
   dbms_output.put_line(i);
end;
declare
  vsal EMP.sal%type;
begin
  --将查询出的结果赋值给vsal
  select sal into vsal from emp where empno = 7369;
  
  dbms_output.put_line(vsal);
end;
select * from emp;
declare
 age number(10,2):=&aaa;
  begin
    if age<18 then
      dbms_output.put_line('小孩子');
    elsif age>18 and age<25 then
     dbms_output.put_line('青年');
     elsif age>25 and age<30 then
       dbms_output.put_line('中年');
      else 
         dbms_output.put_line('老年');
      end if;
   end;
  -- while 循环 
declare
    i number:=1;
   begin
     while i<=10 loop
      dbms_output.put_line('i='||i);
      i:=i+1;
      end loop;
    end;
    -- for 循环倒叙
declare

 begin
    for i in reverse 1..10 loop
      dbms_output.put_line(i);
 end loop;
 end;
 -- for循环正序
 declare
  begin
    for i in 1..10 loop
      dbms_output.put_line(i);
    end loop;
  end;
declare 
  i number:=1;
  begin
     loop
     exit when i>10;
     dbms_output.put_line(i);
     i:=i+1;
     end loop;
  end;