如何在 rethinkdb 中做两个字段计数数据？

Question

我想在 rethinkdb 中做两个字段计数数据 python。示例：我的 table 是.. 频道table

{
"channel_name":  "channel01" ,
"id":  "58115c5b-af1f-4b1a-b572-20611ba34ee5" ,
"userid":  "b9936a2f-6cea-41ef-a7f8-1812c3192112" ,
"visibility":  "Public"
}

{
"channel_name":  "channel02" ,
"id":  "1852fac4-3056-46d9-9dfa-2cd969872daa" ,
"userid":  "b9936a2f-6cea-41ef-a7f8-1812c3192112" ,
"visibility":  "Public"
}

{
"channel_name":  "channel03" ,
"id":  "4304fa69-173b-4284-9bf8-d9078bb018f8" ,
"userid":  "ef5e924e-9cab-44a1-a381-16b35d0d7578" ,
"visibility":  "Public"
}

事件table

{
"content":  "Welcome to channel01" ,
"id":  "cc9bb13e-07e1-4ec9-b1ec-4546b8f8feda" ,
"parent":  "channel01" ,
"type":  "message" ,
"user": {
      "user_id":  "b9936a2f-6cea-41ef-a7f8-1812c3192112" ,
               "user_name":  "wymh" 
    } 
}

{
"content":  "hello" ,
"id":  "288847a9-ffb5-4531-bdc3-ddb3effbd993" ,
"parent":  "channel02" ,
"type":  "message" ,
"user": {
      "user_id":  "b9936a2f-6cea-41ef-a7f8-1812c3192112" ,
      "user_name":  "wymh" 
    } 
} 

{
"content":  "hi" ,
"id":  "3232f906-d9f1-43af-a594-5da82376f296" ,
"parent":  "channel02" ,
"type":  "message" ,
"user": {
      "user_id":  "ef5e924e-9cab-44a1-a381-16b35d0d7578" ,
      "user_name":  "waiyan" 
    } 
} 

{
"content":  "Nice to meet you" ,
"id":  "77b7afb3-af98-47a0-84bf-9ac8bd1fe14c" ,
"parent":  "channel02" ,
"type":  "message" ,
"user": {
      "user_id":  "b9936a2f-6cea-41ef-a7f8-1812c3192112" ,
      "user_name":  "wymh" 
    } 
} 

{
"content":  "hi" ,
"id":  "31068384-4734-4733-a7f7-677edd21e557" ,
"parent":  "channel03" ,
"type":  "message" ,
"user": {
      "user_id":  "ef5e924e-9cab-44a1-a381-16b35d0d7578" ,
      "user_name":  "waiyan" 
    } 
}

{
"content":  "hi" ,
"id":  "0b535878-3cac-4619-9c48-f0985a7ee587" ,
"parent":  "channel03" ,
"type":  "message" ,
"user": {
      "user_id":  "7e485c95-f0b6-45f7-8af2-d93bde0ea8a3" ,
      "user_name":  "user01" 
    } 
}

我的查询是：

channel_count =(yield r.table("channel").filter(r.row['visibility'] != 'private').inner_join(
              r.table("events"),
              lambda channel, events:
              (channel["channel_name"] == events["parent"])
          ).zip().group('channel_name').count().run())

我的查询输出数据是：

  {u'channel01': 1, u'channel02': 3, u'channel03': 2}

我想要以下结果：

{'channel01': 1, 'userid': 1}
{'channel02': 3, 'userid': 2}
{'channel03': 2, 'userid': 2}

请帮助我如何编写 python Rethinkdb 查询？

Answer 1

如果您要查找每个频道的唯一用户 ID 数量和事件数量，我会执行以下操作（我将其隔开以使其更具可读性 IMO）...

>>> events_per_channel = (
        r
        .table("channel")
        .filter(r.row['visibility'] != 'private')
        .inner_join(
            r.table("events"),
            lambda channel,
            events: (channel["channel_name"] == events["parent"])
        )
        .zip()
        .map(
            {
                'channel_name': r.row['channel_name'],
                'user_id': r.row['user']['user_id']
            }
        )
        .group('channel_name')
        .count()
        .ungroup()
        .map(
            lambda x:
            {
                'channel_name': x['group'],
                'events': x['reduction'],
                'uniq_user_ids': (
                    r
                    .table('events')
                    .filter(
                        {
                            'parent': x['group']
                        }
                    )
                    .coerce_to('array')
                    .map(lambda y: y['user']['user_id'])
                    .distinct()
                    .count()
               )
            }
    )
    .run()
)
>>> print json.dumps(events_per_channel, indent=4)
[
    {
        "channel_name": "channel01", 
        "events": 1, 
        "uniq_user_ids": 1
    }, 
    {
        "channel_name": "channel02", 
        "events": 3, 
        "uniq_user_ids": 2
    }, 
    {
        "channel_name": "channel03", 
        "events": 2, 
        "uniq_user_ids": 2
    }
]

基本上我所做的是对每个频道的唯一用户数使用嵌套查询以及使用取消分组，因此我可以使用缩减关键字从组中获取原始数据。输出并不完全符合您的要求，因为您要求的是使用通道名称作为键，使用值作为事件数。我所做的是为每个值创建一个键名。如果这不是您真正的意思，请告诉我。

如何在 rethinkdb 中做两个字段计数数据？

How can I do two fields count data in rethinkdb?

python-3.x

rethinkdb-python