MongoDB的彙總查詢集團按日期

Question

我在MongoDB中以下收集

{ _id, startTime, duration } 

所以基本思想是，一個攝像頭俯瞰的人，一旦檢測到它節省了startTime和一個人一個人一旦消失它可以節省持續時間。 所以實體基本上說「一個人出現在X時間，並在Y毫秒的相機範圍內」。 startTime和duration都是數字值。

所以，我要像執行各種查詢： 1.給我每月的人數/年 2.給我的人數每月與持續時間> 5000毫秒

等

雖然我對MongoDB相當陌生，但是我對聚合框架有點麻煩，所以如果有人給我一個關於如何進行上述查詢的想法，以便獲得某種類型的開始。

編輯：

好吧，我已經做了幾次嘗試，但沒有運氣。現在，我的對象具有這種形式：

{ 
    "_id" : ObjectId("52de407c75895eaf5ea99715"), 
    "startTime" : "new Date('02 01 2011 08:36:54')", 
    "duration" : 27000 
} 

，我想這個查詢：

db.collection.aggregate(
     {$project : { 
      year : {$year : "$startTime"} 

     }}, 
     {$group : { 
      _id : {year : "$year"}, 
      count : {$sum : 1} 
     }} 
    ) 

，但我發現以下異常：

Error occurred in performing aggregation 
Command 'aggregate' failed: exception: can't convert from BSON type String to Date (response: { "errmsg" : "exception: can't convert from BSON type String to Date", "code" : 16006, "ok" : 0.0 }) 
Type: MongoDB.Driver.MongoCommandException 
Stack: at MongoDB.Driver.Operations.CommandOperation`1.Execute(MongoConnection connection) 
    at MongoDB.Driver.MongoCollection.RunCommandAs[TCommandResult](IMongoCommand command, IBsonSerializer resultSerializer, IBsonSerializationOptions resultSerializationOptions) 
    at MongoDB.Driver.MongoCollection.RunCommandAs[TCommandResult](IMongoCommand command) 
    at MongoDB.Driver.MongoCollection.Aggregate(IEnumerable`1 operations) 
    at MangoUI.ComAggregate.kRemove_Click(Object sender, EventArgs e) 
Inputs:: 
Command: aggregate 
Ok:  False 
ErrorMsg: exception: can't convert from BSON type String to Date 
Request: { "aggregate" : "person", "pipeline" : [{ "$project" : { "year" : { "$year" : "$startTime" } } }, { "$group" : { "_id" : { "year" : "$year" }, "count" : { "$sum" : 1 } } }] } 
Response: { "errmsg" : "exception: can't convert from BSON type String to Date", "code" : 16006, "ok" : 0.0 } 

Answer 1

你可以做他們與聚合框架。

給我每月的人數/年

db.collection.aggregate(
    {$project : { 
     year : {$year : "$startTime"}, 
     month : {$month : "$startTime"} 
    }}, 
    {$group : { 
     _id : {year : "$year", month : "$month"}, 
     count : {$sum : 1} 
    }} 
) 

給我每月人持續時間> 5000毫秒

db.collection.aggregate(
    {$project : { 
     year : {$year : "$startTime"}, 
     month : {$month : "$startTime"}, 
     duration: {$cond: [{$gt: ['$duration', 5000]}, 1, 0]} 
    }}, 
    {$group : { 
     _id : {year : "$year",month : "$month"}, 
     duration : {$sum : "$duration"} 
    }} 
) 

欲瞭解更多信息，數量檢查Aggregation Framework.

Answer 2

請參考MongoDB的兼容數據格式http://docs.mongodb.org/manual/reference/bson-types/#document-bson-type-date

以下是測試聚合的方法。

rs1:PRIMARY> 
rs1:PRIMARY> db.dbversitycol.insert({ "_id" : "1", "LastUpdatedOn" : new Date() , "company" : "microsoft" }) 
rs1:PRIMARY> db.dbversitycol.insert({ "_id" : "2", "LastUpdatedOn" : new Date() , "company" : "google" }) 
rs1:PRIMARY> db.dbversitycol.insert({ "_id" : "3", "LastUpdatedOn" : new Date() , "company" : "ibm" }) 
rs1:PRIMARY> db.dbversitycol.insert({ "_id" : "4", "LastUpdatedOn" : new Date() , "company" : "cisco" }) 
rs1:PRIMARY> db.dbversitycol.insert({ "_id" : "5", "LastUpdatedOn" : new Date() , "company" : "dbversity.com" }) 
rs1:PRIMARY> 
rs1:PRIMARY> db.dbversitycol.find() 
{ "_id" : "1", "LastUpdatedOn" : ISODate("2014-11-28T13:09:13.203Z"), "company" : "microsoft" } 
{ "_id" : "2", "LastUpdatedOn" : ISODate("2014-11-28T13:09:13.207Z"), "company" : "google" } 
{ "_id" : "3", "LastUpdatedOn" : ISODate("2014-11-28T13:09:13.210Z"), "company" : "ibm" } 
{ "_id" : "4", "LastUpdatedOn" : ISODate("2014-11-28T13:09:13.213Z"), "company" : "cisco" } 
{ "_id" : "5", "LastUpdatedOn" : ISODate("2014-11-28T13:09:14.035Z"), "company" : "dbversity.com" } 
rs1:PRIMARY> 
rs1:PRIMARY> 
rs1:PRIMARY> db.dbversitycol.aggregate(
... { 
...  "$project" : 
...  { 
...  _id : 0, 
...  "datePartDay" : {"$concat" : [ 
...   {"$substr" : [{"$dayOfMonth" : "$LastUpdatedOn"}, 0, 2]}, "-", 
...   {"$substr" : [{"$month" : "$LastUpdatedOn"}, 0, 2]}, "-", 
...   {"$substr" : [{"$year" : "$LastUpdatedOn"}, 0, 4]} 
...  ] } 
...  } 
... }, 
... { "$group" : 
...  { "_id" : "$datePartDay", "Count" : { "$sum" : 1 } } 
...  } 
...) 
{ "result" : [ { "_id" : "28-11-2014", "Count" : 5 } ], "ok" : 1 } 
rs1:PRIMARY> 
rs1:PRIMARY> 



rs1:PRIMARY> db.dbversitycol.aggregate(
...  {$project : { 
...   year : {$year : "$LastUpdatedOn"}, 
...   month : {$month : "$LastUpdatedOn"} 
...  }}, 
...  {$group : { 
...   _id : {year : "$year", month : "$month"}, 
...   count : {$sum : 1} 
...  }} 
...) 
{ 
     "result" : [ 
       { 
         "_id" : { 
           "year" : 2014, 
           "month" : 11 
         }, 
         "count" : 5 
       } 
     ], 
     "ok" : 1 
} 
rs1:PRIMARY> 

你可以在http://www.dbversity.com/