PLSQL程序控制结构

if语句，null语句=====================select * from scott.emp;declarev_job scott.emp.job%type;beginselect job into v_job from scott.emp where lower(ename)=lower('&name');    if v_job='MANAGER' then        update scott.emp set comm=nvl(comm,0)+100 where  lower(ename)=lower('&name');     elsif v_job='PRESIDENT' then         update scott.emp set comm=nvl(comm,0)+10  where lower(ename)=lower('&name');elsenull;end if;end;//case表达式  ====================== select * from scott.emp     declare    v_salary  scott.emp.sal%type;   bonus_amount number;   begin   select sal into v_salary from scott.emp where ename='&ename';    bonus_amount :=     case     when v_salary >=1000 and v_salary <=2000 then 150     when v_salary >2000 and v_salary <=3000 then 100    when v_salary >3000  then 50    else 0    end *10;    dbms_output.put_line(bonus_amount);     end;//for循环=============reverse关键字为倒序插入    select * from temp4    create table temp4(    tId number(3)  primary key     )declare      begin      for i  in  1..10       loop           insert into temp4 values(i);       end loop;   end;//goto语句实现循环控制select * from temp5create table temp5(tId number(3))declare i int :=1; begin     loop      insert into temp5 values(i);   if i=10  then    goto end_loop;   end if;  i:=i+1;    end loop;    <<end_loop>>dbms_output.put_line('dsa'); end;