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我有一个名为 Packages 的表，其中包含一些数据和一个包含其他信息的相关表。它是这样设置的：

Name|Version|Architecture|Date|id

在另一个名为 Distribution 的表中，我有这个：

repo|id

id 相互引用。我希望能够获得某个分组的最新（按日期排序）。我想按名称、架构和存储库分组。问题是我似乎无法让正常的 best-n-group 正常工作，因为我必须跨表。这是我到目前为止所拥有的

select
    p1.Name,
    p1.Version,
    p1.Arch,
    d1.repo,
    p1.Date
from Packages as p1
inner join Distribution as d1
    on p1.id = d1.id
inner join (
    select
        Name,
        Arch,
        repo,
        max(Date) as Date
    from Packages
    inner join Distribution
        on Packages.id = Distribution.id
    group by
        Name,
        Arch,
        repo
) as sq
    on p1.Name = sq.Name and p1.Arch = sq.Arch and d1.repo = sq.repo and p1.Date = sq.Date

问题是它似乎没有正确地对 repo 进行分组。它没有给我一个独特的回购。

编辑：我想为每个 repo 获取最新版本。所以我必须在每个回购中获得最大日期，然后进行分组。

编辑 2：我使用了一个答案来得到这个：

select p1.Name, p1.Version, p1.Arch, d1.repo, p1.Date
from Packages as p1 inner join
    Distribution as d1
    on p1.id = d1.id inner join (
        select Name, Arch, repo, max(Date) as Date
        from Packages inner join Distribution
            on Packages.id = Distribution.id
        group by Name, Arch, repo
    ) as sq
    on p1.Name = sq.Name and p1.Arch = sq.Arch and d1.repo = sq.repo and p1.Date = sq.Date

这似乎对我有用。

4

1 回答 1

1

我想你想repo从最大查询中删除：

select p1.Name, p1.Version, p1.Arch, d1.repo, p1.Date
from Packages p1 inner join
     Distribution d1
     on p1.id = d1.id inner join
     (select Name, Arch, max(Date) as Date
      from Packages
      group by Name, Arch
     ) sq
     on p1.Name = sq.Name and p1.Arch = sq.Arch and p1.Date = sq.Date;

编辑：

如果不是所有 repos 都有日期，那么您希望在子查询中按分布进行过滤。但是，您仍然不想放入repo聚合：

select p1.Name, p1.Version, p1.Arch, d1.repo, p1.Date
from Packages p1 inner join
     Distribution d1
     on p1.id = d1.id inner join
     (select Name, Arch, max(Date) as Date
      from Packages p join
           Distribution d
           on p.id = d.id
      group by Name, Arch
     ) sq
     on p1.Name = sq.Name and p1.Arch = sq.Arch and p1.Date = sq.Date;
于 2013-08-26T15:02:03.887 回答