aggregate基礎 使用記錄

mongoDB中聚合(aggregate)的具體使用

我們可以用$指定字段來表示選定的document的field,另外可以使用$$ROOT來表示選定的document的所有內容（例如:chosenDocument: {$push: '$$ROOT'}）

示例：按條件查找數據，將找到的結果進行排序並分組，並且需要返回分組后的所有文檔內容；$push, $addToSet實現的功能一樣

GrowthRecordSync.aggregate([
                { $match: cond },
                { $sort: {time_point: 1}},
                { $group: {
                    _id: { $year: "$time_point"}, 
                    count:{ $sum: 1}, 
                    result:{ 
                        // $addToSet: "$$ROOT"}
                        $push: "$$ROOT"}
                    }
                },
                { $sort: {_id: 1}}
            ],cb)

結果：

"data": [
    {
      "_id": 2018,
      "count": 1,
      "result": [
        {
          "_id": "5c514c3675844415dac30efc",
          "createDate": "2019-01-30T07:03:18.000Z",
          "lastModified": "2019-01-30T07:03:18.285Z",
          "time_point": "2018-11-14T00:00:00.000Z",
          "type": "entry",
          "eveid": "5bf60a4dfdb0ed18594b8ce6",
          "title": "A職",
          "description": "",
          "client": "584ec02dacbd274539b4ab16",
          "people": "5bf60a4dfdb0ed18594b8ce6",
          "people_no": "00000009",
          "people_name": "成成",
          "ou_name": "啊總經辦",
          "ou": "5858a50bdc2a25120dcf5163",
          "terminated": false,
          "activate": true,
          "block_reason": "",
          "block": false,
          "validTo": "9999-12-31T15:59:59.999Z",
          "validFrom": "2019-01-29T16:00:00.000Z",
          "__v": 0
        }
      ]
    },
    {
      "_id": 2019,
      "count": 2,
      "result": [
        {
          "_id": "5c6a979b1a921a16cc592fac",
          "createDate": "2019-02-18T11:31:39.000Z",
          "lastModified": "2019-02-18T11:31:39.062Z",
          "client": "584ec02dacbd274539b4ab16",
          "people": "5bf60a4dfdb0ed18594b8ce6",
          "people_no": "00000009",
          "ou_name": "33總經辦",
          "ou": "5858a50bdc2a25120dcf5163",
          "time_point": "2019-02-20T00:00:00.000Z",
          "create_people": "585a17ae2098688d02eeade7",
          "type": "cus",
          "eveid": "5c6a979b1a921a16cc592fab",
          "title": "098765432dd1",
          "description": "88776787888",
          "terminated": false,
          "activate": true,
          "block_reason": "",
          "block": false,
          "validTo": "9999-12-31T15:59:59.999Z",
          "validFrom": "2019-02-17T16:00:00.000Z",
          "img": [
            "5c6a97221a921a16cc592fa5"
          ],
          "__v": 0
        },
        {
          "_id": "5c6a97271a921a16cc592fa9",
          "createDate": "2019-02-18T11:29:43.000Z",
          "lastModified": "2019-02-18T11:29:43.810Z",
          "client": "584ec02dacbd274539b4ab16",
          "people": "5bf60a4dfdb0ed18594b8ce6",
          "people_no": "00000009",
          "ou_name": "33總經辦",
          "ou": "5858a50bdc2a25120dcf5163",
          "time_point": "2019-02-20T00:00:00.000Z",
          "create_people": "585a17ae2098688d02eeade7",
          "type": "cus",
          "eveid": "5c6a97271a921a16cc592fa8",
          "title": "098765432dd1",
          "description": "88776787888",
          "terminated": false,
          "activate": true,
          "block_reason": "",
          "block": false,
          "validTo": "9999-12-31T15:59:59.999Z",
          "validFrom": "2019-02-17T16:00:00.000Z",
          "img": [
            "5c6a97221a921a16cc592fa5"
          ],
          "__v": 0
        }
    ]
}

 

選取部分字段，將"$$ROOT"換成下面想要的字段即可

$push: {"_id": "$_id", "process_code": "$process_code","process_name":"$process_name","wf_type":"$wf_type","cus_approve_event":"$cus_approve_event"}

 

mongodb-模糊查詢+聚合函數+連表查詢+排序

 在 mongodb中用的主要是$regex來實現模糊查詢

$project：修改輸入文檔的結構。可以用來重命名、增加或刪除域，也可以用於創建計算結果以及嵌套文檔。 $match：用於過濾數據，只輸出符合條件的文檔。$match使用MongoDB的標准查詢操作。 $limit：用來限制MongoDB聚合管道返回的文檔數。 $skip：在聚合管道中跳過指定數量的文檔，並返回余下的文檔。 $unwind：將文檔中的某一個數組類型字段拆分成多條，每條包含數組中的一個值。
　　例：table1: 

{_id:1,result:[
    {name:"a",age:"18"},
    {name:"b",age:"19"},
    {name:"c",age:"20"}]
} 

執行db.table1.aggregate({"$unwind":"$result"})后的結果為

{id:1,result:{name:"a",age:"18"}},
{id:1,result:{name:"b",age:"19"}},
{id:1,result:{name:"c",age:"20"}} 

$group：將集合中的文檔分組，可用於統計結果。 $sort：將輸入文檔排序后輸出。 $geoNear：輸出接近某一地理位置的有序文檔。

聚合aggregate 管道運算符（全）

 

$setIntersection: 是取兩個數組的交集

isShow: { $setIntersection: [ "$positions", current_positions ] }

 

實用注意事項記錄：

ProcessDefine.aggregate({
        $match: {process_code: 'CustomizeAttendance', block: false, client: ObjectId(client)}
    },{
        $lookup: {  //lookup連表查詢后都是數組，就算原來的結構是對象的連表后查出的結構也是數據
            from: 'cusitemapproveevents',    // 數據庫中的表名（全部小寫，默認加s）
            localField: 'cus_approve_event',
            foreignField: '_id',
            as: 'cus_approve_event',
        }
    },{
        $unwind:{ // 將數組結構換為對象結構
            path: '$cus_approve_event',
            preserveNullAndEmptyArrays:true
        }
    },
    {
        $group:{
            _id: {cus_approve_event:"$cus_approve_event._id", approve_name: "$cus_approve_event.approve_name"},   //分組，一個值的分組_id:"$cus_approve_event._id"， 對兩個值進行分組，傳對象。
　　　　　　　count:{ $sum: 1}, 
　　　　　　  result:{ 
　　　　　　　　// $push: "$$ROOT"   // 全部字段
　　　　　　　　$push: {"_id": "$_id", "process_code": "$process_code","process_name":"$process_name","wf_type":"$wf_type","cus_approve_event":"$cus_approve_event"} } }   // 只選需要的字段
　　}).exec(function(err,data){
 　　　　res.json(data); 
　　　}) 
}