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我正在尝试在 github 存档（http://www.githubarchive.org/）数据上使用 Google BigQuery 来获取存储库在其最新事件发生时的统计信息，并且我正在尝试为最多的存储库获取此信息观察者。我意识到这很多，但我觉得我真的很接近在一次查询中得到它。

这是我现在的查询：

SELECT repository_name, repository_owner, repository_organization, repository_size,  repository_watchers as watchers, repository_forks as forks, repository_language, MAX(PARSE_UTC_USEC(created_at)) as time
FROM [githubarchive:github.timeline]
GROUP EACH BY repository_name, repository_owner, repository_organization, repository_size, watchers, forks, repository_language
ORDER BY watchers DESC, time DESC
LIMIT 1000

唯一的问题是我得到了来自最高关注存储库（twitter bootstrap）的所有事件：

结果：

Row repository_name repository_owner    repository_organization repository_size watchers    forks   repository_language time     
1   bootstrap           twbs                    twbs                   83875      61191     21602   JavaScript          1384991582000000     
2   bootstrap           twbs                    twbs                   83875      61190     21602   JavaScript          1384991337000000     
3   bootstrap           twbs                    twbs                   83875      61190     21603   JavaScript          1384989683000000

...

我怎样才能让它返回一个repository_name的单个结果（最近的，又名Max（time））？

我试过了：

SELECT repository_name, repository_owner, repository_organization, repository_size, repository_watchers as watchers, repository_forks as forks, repository_language, MAX(PARSE_UTC_USEC(created_at)) as time
FROM [githubarchive:github.timeline]
WHERE PARSE_UTC_USEC(created_at) IN (SELECT MAX(PARSE_UTC_USEC(created_at)) FROM [githubarchive:github.timeline])
GROUP EACH BY repository_name, repository_owner, repository_organization, repository_size, watchers, forks, repository_language
ORDER BY watchers DESC, time DESC
LIMIT 1000

不确定这是否可行，但没关系，因为我收到错误消息：

Error: Join attribute is not defined: PARSE_UTC_USEC

任何帮助都会很棒，谢谢。

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1 回答 1

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该查询的一个问题是，如果有两个操作同时发生，您的结果可能会混淆。如果您只是按存储库名称分组以获得每个存储库的最大提交时间，然后加入反对以获得您想要的其他字段，您可以获得您想要的内容。例如：

SELECT
  a.repository_name as name,
  a.repository_owner as owner,
  a.repository_organization as organization,
  a.repository_size as size,
  a.repository_watchers AS watchers,
  a.repository_forks AS forks,
  a.repository_language as language,
  PARSE_UTC_USEC(created_at) AS time  
FROM [githubarchive:github.timeline] a
JOIN EACH
  (
     SELECT MAX(created_at) as max_created, repository_name 
     FROM [githubarchive:github.timeline]
     GROUP EACH BY repository_name
  ) b
  ON 
  b.max_created = a.created_at and
  b.repository_name = a.repository_name
ORDER BY watchers desc
LIMIT 1000
于 2013-11-21T02:13:02.677 回答