1.显示效果 2.数据insert脚本 insert into CITY(id,text,pid) values('1','城市',null)insert into CITY(id,text,pid) values('2','北京市','1')insert into CITY(id,text,pid) values('3','上海市','1')insert into CITY(id,text,pid) values('4','天津市','1')insert into CITY(id,text,…