Mongo Group和两个字段的和 [英] Mongo Group and sum with two fields

问题描述

我有类似的文件:

{
   "from":"[e-mail]",
   "to" :"[e-mail]",
   "email": "Hi hello"
}

我们如何计算从和到"或从和到"的总数? 就像两个人之间的交流很重要吗?

How can we calculate count of sum "from and to" or "to and from"? Like communication counts between two people?

我能够计算单向总和.我想双向求和.

I am able to calculate one way sum. I want to have sum both ways.

db.test.aggregate([
      { $group: {
         "_id":{ "from": "$from", "to":"$to"},
           "count":{$sum:1} 
         }
      },
      { 
        "$sort" :{"count":-1}
      }
])

推荐答案

由于您需要计算在两个地址之间交换的电子邮件数量，因此将一个统一的between字段投影为以下:

Since you need to calculate number of emails exchanged between 2 addresses, it would be fair to project a unified between field as following:

db.a.aggregate([
    { $match: {
        to: { $exists: true },
        from: { $exists: true },
        email: { $exists: true }
    }}, 
    { $project: {
        between: { $cond: { 
            if: { $lte: [ { $strcasecmp: [ "$to", "$from" ] }, 0 ] }, 
            then: [ { $toLower: "$to" }, { $toLower: "$from" } ], 
            else: [ { $toLower: "$from" }, { $toLower: "$to" } ] }
        } 
    }},
    { $group: {
         "_id": "$between",
         "count": { $sum: 1 } 
    }},
    { $sort :{ count: -1 } }
])

从示例中可以很清楚地看出统一逻辑:这是两个电子邮件的按字母顺序排序的数组.如果您信任自己的数据，则$match和$toLower部分是可选的.

Unification logic should be quite clear from the example: it is an alphabetically sorted array of both emails. The $match and $toLower parts are optional if you trust your data.

示例中使用的运算符的文档:

Documentation for operators used in the example:

• $ match
• $ exists
• $ project
• $ cond
• $ lte
• $ strcasecmp
• $ toLower
• $ group
• $ sum
• $ sort

• $match
• $exists
• $project
• $cond
• $lte
• $strcasecmp
• $toLower
• $group
• $sum
• $sort

这篇关于Mongo Group和两个字段的和的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！