我有三个表：friends，locations，friend_location

friend_location是一个联接表，用于允许friends和之间的多对多关系locations，因此这些表将如下所示：

朋友们

ID  | Name
1   | Jerry
2   | Nelson
3   | Paul

地点

ID  | Date       | Lat   | Lon 
1   | 2012-03-01 | 34.3  |  67.3
2   | 2011-04-03 | 45.3  |  49.3
3   | 2012-05-03 | 32.2  |  107.2

friend_location

Friend_ID  | Location_id
1          |  2
2          |  1
3          |  3
2          |  2

我想做的就是获取每个朋友的最新位置。

结果

ID  | Friend | Last Know Location  | last know date
1   | Jerry  |  45.3 , 49.3        | 2011-04-03
2   | Nelson |  34.3 , 67.3        | 2012-03-01
3   | Paul   |  32.2 , 107.2       | 2012-05-03

这是我在查看各种示例之后尝试过的方法，但是它返回了许多结果，并且是不正确的：

    select f.id , f.name , last_known_date
    from friends f, (

    select distinct fl.friend_id as friend_id, fl.location_id as location_id, m.date as last_known_date
    from friend_location fl

    inner join (
        select location.id as id, max(date) as date
        from location
        group by location.id
    ) m

    on fl.location_id=m.id

    ) as y
    where f.id=y.friend_id

任何建议将不胜感激。