-- loop的三种形式
(1).LOOP
(2).WHILE ... LOOOP
(3).FOR ... LOOP

1.基本的LOOP语句
SET serveroutput ON;

-- exit ... when 结束循环

DECLARE 
    v_value NUMBER(8) := -3;
BEGIN
  <<value_loop>>  -- 循环标记
  LOOP
    dbms_output.put_line(‘v_value = http://www.mamicode.com/‘ || v_value);>