How can I group data while fetching from mongodb using go?

huangapple
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英文:

How can I group data while fetching from mongodb using go?

问题

我有一个名为"myplace"的集合，它有以下字段：place_name（地点名称）、city（城市）、latitude（纬度）、longitude（经度）。

文档格式如下：

  1. {
  2.     "_id" : ObjectId("544a2147785b707b340ed6c7"),
  3.     "latitude" : 12.36547,
  4.     "longitude" : 1.235689,
  5.     "place_name" : "some_place",
  6.     "city" : "City1"
  7. }
  8. {
  9.     "_id" : ObjectId("544a2147785b707b340ed6c7"),
  10.     "latitude" : 12.36547,
  11.     "longitude" : 1.235689,
  12.     "place_name" : "some_place",
  13.     "city" : "City3"
  14. }
  15. {
  16.     "_id" : ObjectId("544a2147785b707b340ed6c7"),
  17.     "latitude" : 12.36547,
  18.     "longitude" : 1.235689,
  19.     "place_name" : "some_place",
  20.     "city" : "City1"
  21. }
  22. {
  23.     "_id" : ObjectId("544a2147785b707b340ed6c7"),
  24.     "latitude" : 12.36547,
  25.     "longitude" : 1.235689,
  26.     "place_name" : "some_place",
  27.     "city" : "City2"
  28. }
  29. {
  30.     "_id" : ObjectId("544a2147785b707b340ed6c7"),
  31.     "latitude" : 12.36547,
  32.     "longitude" : 1.235689,
  33.     "place_name" : "some_place",
  34.     "city" : "City2"
  35. }

如何将具有相同城市的数据分组？意思是我需要一个包含所有具有City1的数据的数组，第二个数组包含所有具有City2的数据，依此类推。

英文:

I have a collection named "myplace" It has the following fileds place_name, city, latitude, longitude.

Doc format

  1. {
  2.       "_id" : ObjectId("544a2147785b707b340ed6c7"),
  3.       "latitude" : 12.36547,
  4.       "longitude" : 1.235689,
  5.       "place_name" : "some_place",
  6.       "city" : "City1"
  7. }
  8. {
  9.       "_id" : ObjectId("544a2147785b707b340ed6c7"),
  10.       "latitude" : 12.36547,
  11.       "longitude" : 1.235689,
  12.       "place_name" : "some_place",
  13.       "city" : "City3"
  14. }
  15. {
  16.       "_id" : ObjectId("544a2147785b707b340ed6c7"),
  17.       "latitude" : 12.36547,
  18.       "longitude" : 1.235689,
  19.       "place_name" : "some_place",
  20.       "city" : "City1"
  21.  }
  22.  {
  23.       "_id" : ObjectId("544a2147785b707b340ed6c7"),
  24.       "latitude" : 12.36547,
  25.       "longitude" : 1.235689,
  26.       "place_name" : "some_place",
  27.       "city" : "City2"
  28. }
  29. {
  30.       "_id" : ObjectId("544a2147785b707b340ed6c7"),
  31.       "latitude" : 12.36547,
  32.       "longitude" : 1.235689,
  33.       "place_name" : "some_place",
  34.       "city" : "City2"
  35. }

How can I group the data with same city? Meaning I need array of json result first array should contain all the data which having city1 second array conatins all the data which having city2 and so on

答案1

得分: 2

你可以在Mongo中更容易地完成这个操作，使用聚合框架。

  1. db.yourCollection.aggregate([
  2.   {
  3.     $group: {
  4.       _id: "$city",
  5.       details: {
  6.         $push: {
  7.           latitude: "$latitude",
  8.           longitude: "$longitude",
  9.           place_name: "$place_name"
  10.         }
  11.       }
  12.     }
  13.   }
  14. ])

我认为这应该可以工作，但我目前无法在工作中实际尝试。希望对你有帮助！

英文:

You could do it in Mongo itself more easily in my opinion. Use the aggregation framework.

  1. db.yourCollection.aggregate([{$group:{_id: "$city", details:{$push: {latitude:  "$latitude",  longitude: "$longitude", place_name:"$place_name"}}}}])

I think this should work, I can't actually try it at the moment at work. hope it helps!

答案2

得分: 1

如果你正在使用mgo，简单的排序就可以解决问题。在这里，我们首先按城市排序，然后按名称排序：

  1. query1 := collection.Find(nil).Sort("city", "place_name")
英文:

If you are using mgo, a simple sort should do the trick. Here we search first by city and then by name:

  1. query1 := collection.Find(nil).Sort("city", "place_name")

huangapple
  • 本文由 发表于 2014年11月5日 18:25:43
  • 转载请务必保留本文链接：https://go.coder-hub.com/26754794.html
  • go
  • mgo
  • mongodb
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