sql语句实现公交换乘，大神进来帮忙解决一下呢！！！！！！！

用的Mysql 5.5数据库
--站点表
create table station_info(
station_id int(4) primary key auto_increment,
station_name varchar(20) not null unique
);
--路线表
create table route_info(
route_id int(4),
route_name varchar(20) not null unique,
start_stationId int not null, --起始站点
end_stationId int not null, --终点站点
);
--路线站点表
create table route_station(
id int(4) primary key auto_increment,
route_id int(4),
station_id int(4) not null,
position int(2) not null,--站点所处路线中位置
upordown int(1) not null --上行或下行(1上2下)
);

我写了一个直达查询语句：
select distinct rs.route_id from route_station rs, route_station rsa
where rs.route_id = rsa.route_id and (rs.station_id = 1 and rsa.station_id = 5)

对于存储过程不会写，能否用sql语句实现，在处理一次换乘和二次换乘的时候写了很多语句，结果就乱了，不用考虑什么最短路径之类的
比如在处理一次换乘的时候，我是先找出换乘站点，然后再通过换乘站点通过直达查询找出换乘路线，多个换乘站点的时候
不知道怎么处理
二次换乘先是找出换乘路线，然后再后面处理感觉比较混乱了

比如说我输入S1-S8,一次换乘想要输出的效果如下：
route_id station_id（换乘站点） route_id(换乘路线)
10 S2/S7 11
10 S2 13
14 S9 12
14 S6 11

测试语句：

10路：S1 - S2 - S3 - S4 - S5 - S7
11路：S2 - S6 - S7 - S8
12路：S8 - S9 - S10
13路：S11 - S2 - S8
14路：S1 - S12 - S6 - S9


insert into station_info values(1,'S1');
insert into station_info values(2,'S2');
insert into station_info values(3,'S3');
insert into station_info values(4,'S4');
insert into station_info values(5,'S5');
insert into station_info values(6,'S6');
insert into station_info values(7,'S7');
insert into station_info values(8,'S8');
insert into station_info values(9,'S9');
insert into station_info values(10,'S10');
insert into station_info values(11,'S11');
insert into station_info values(12,'S12');

insert into route_info values(10,'10',1,7);
insert into route_info values(11,'11',2,8);
insert into route_info values(12,'12',8,10);
insert into route_info values(13,'13',11,8);
insert into route_info values(14,'14',1,9);

insert into route_station values(1,10,1,1,1);
insert into route_station values(2,10,2,2,1);
insert into route_station values(3,10,3,3,1);
insert into route_station values(4,10,4,4,1);
insert into route_station values(5,10,5,5,1);
insert into route_station values(6,10,7,6,1);
insert into route_station values(7,11,2,1,1);
insert into route_station values(8,11,6,2,1);
insert into route_station values(9,11,7,3,1);
insert into route_station values(10,11,8,4,1);
insert into route_station values(11,12,8,1,1);
insert into route_station values(12,12,9,2,1);
insert into route_station values(13,12,10,3,1);
insert into route_station values(14,13,11,1,1);
insert into route_station values(15,13,2,2,1);
insert into route_station values(16,13,8,3,1);
insert into route_station values(17,14,1,1,1);
insert into route_station values(18,14,12,2,1);
insert into route_station values(19,14,6,3,1);
insert into route_station values(20,14,9,4,1);
commit;