Question

我正在使用mongoDB数据库在rails上开发一个ruby站点。我是mongoDB的初学者，我想使用多个键对数据进行排序。我的一个系列如下所示。

dd_users
{
   "_id": ObjectId("4e9bcbdb1d41c866c600004e"),   
   "name": "Ram",
   "score":5
    "created_at": ISODate("2011-10-17T06: 31: 55.0Z"),
}
{
   "_id": ObjectId("4e9bcbdb1d41c866c600004f"),   
   "name": "Robert",
   "score":1
   "created_at": ISODate("2011-10-12T06: 31: 55.0Z"),
}
{
   "_id": ObjectId("4e9bcbdb1d41c866c600004g"),   
   "name": "Molly Bracken",
   "score":3
   "created_at": ISODate("2011-10-15T06: 31: 55.0Z"),
}
{
   "_id": ObjectId("4e9bcbdb1d41c866c600005k"),   
   "name": "Ninou-Co France",
   "score":5
   "created_at": ISODate("2011-10-16T06: 31: 55.0Z"),
}

我想按照“得分”和“created_at”的降序对记录进行排序。我使用mongomapper查询作为 1.DdUser.where（{“name”=＆gt; {“$ ne”=＆gt; nil}）。sort（[[“score”，“desc”]，[“created_at”，“desc”]]）。但我只得到了得分的结果。

我期待结果

{
   "_id": ObjectId("4e9bcbdb1d41c866c600004e"),   
   "name": "Ram",
   "score":5
    "created_at": ISODate("2011-10-17T06: 31: 55.0Z"),
}
{
   "_id": ObjectId("4e9bcbdb1d41c866c600005k"),   
   "name": "Ninou-Co France",
   "score":5
   "created_at": ISODate("2011-10-16T06: 31: 55.0Z"),
}
{
   "_id": ObjectId("4e9bcbdb1d41c866c600004g"),   
   "name": "Molly Bracken",
   "score":3
   "created_at": ISODate("2011-10-15T06: 31: 55.0Z"),
}
{
   "_id": ObjectId("4e9bcbdb1d41c866c600004f"),   
   "name": "Robert",
   "score":1
   "created_at": ISODate("2011-10-12T06: 31: 55.0Z"),
}

Answer 1

DdUser.where("name" => { "$ne" => nil } ).sort(["score","desc"], ["created_at","desc"])

Answer 2

我个人没有使用Mongomapper，因此以下代码未经测试：

DdUser.where("name" => { "$ne" => nil } ).sort([:score.desc, :created_at.desc])

Answer 3

对我来说有用的是

DdUser.where("name" => { "$ne" => nil } ).sort(:score.desc, :created_at.desc)

Mongodb - 使用多个字段进行ROR排序

3 个答案: