关于MySQL游标的嵌套使用

前几天群里有人问MySQL的游标能不能嵌套使用，想当然地以为不能，后来试了下，居然可以，唉，不能随便想当然啊。例子如下：

CREATE PROCEDURE curdemo() 
  NOT DETERMINISTIC 
  CONTAINS SQL 
  SQL SECURITY DEFINER 
  COMMENT '' 
BEGIN 
  declare done1,done2 int default 0; 
  declare name1,name2 varchar(20); 
  declare id1,id2 int;
  declare cur1 cursor for select id,name from test1; 
  declare continue handler for not found set done1 = 1;
  open cur1;
  repeat 
    fetch cur1 into id1, name1; 
    if not done1 then 
      insert into test3(name) values(name1); 
      begin 
        declare cur2 cursor for select id,name from test2; 
        declare continue handler for not found set done2 = 1; 
        open cur2; 
        repeat 
          fetch cur2 into id2,name2; 
          if not done2 then 
            insert into test3(name) values(name2); 
          end if; 
        until done2 end repeat; 
        close cur2; 
        set done2=0; 
      end; 
    end if; 
    until done1 
  end repeat; 
  close cur1; 
  commit; 
END;