SQLite3，将多行合并为一行

我有两张表：城市（如C）和路线（如R）

C:

R:

（我的期望）：我希望将我的表合并并连接到以下表单：

 ____ ______ ____________ ____ __________ __________
| id | from | fromAsText | to | toAsText | distance |
|____|______|____________|____|__________|__________|
| 1  | 1    | A          | 2  | B        | 100      |
| 2  | 2    | B          | 1  | A        | 100      | 
|____|______|____________|____|__________|__________|

添加一个值不是问题

    SELECT
    r.*
    s.city as fromAsText
    FROM
    routes as r,
    cities as s
    WHERE
    r.from = s.id

---

但是我不知道如何实现我的目标！谢谢

只需加入城市表两次：

select r.id, r.from, c_from.city as from_city, r.to, c_to.city as to_city, r.distance
from routes r
join cities c_from on c_from.id = r.from
join cities c_to on c_to.id = r.to
order by r.id;

---

您确定预期结果正确吗？请不要使用逗号分隔的联接。在标准SQL 1992中有冗余！改为使用显式连接：

从路由作为r内部连接城市作为c ON c.id=r.FROM

。Argh，出现错误，预期已更新

    SELECT
    r.*
    s.city as fromAsText
    FROM
    routes as r,
    cities as s
    WHERE
    r.from = s.id

select r.id, r.from, c_from.city as from_city, r.to, c_to.city as to_city, r.distance
from routes r
join cities c_from on c_from.id = r.from
join cities c_to on c_to.id = r.to
order by r.id;