表單生成器(Form Builder)之mongodb表單數據查詢——統計查詢求和

　　上一篇筆記僅是記錄了一下簡單的關聯查詢，根據筆記中的場景：將某一車輛關聯的耗損記錄全部放在了一個字段當中。不知道現在中有沒有這種場景，我們的應用中沒有類似的場景，可能我們更關注的是某車輛的總耗損金額和總營收金額、總里程數等，因此這篇筆記記錄一下怎么得到這些數據。要想獲取這些記錄我們首先想到的就是先按照車輛ID分組之后再對指定字段求和，可能是先入為主的原因（有了上一篇筆記），我沒有按照傳統的思路走下去，而是想着看看能不能在上一篇筆記的基礎之上得到想要的結果。

　　我們沿着這條路在分析一下，車輛相關的耗損和營收都可以放到一個字段中。也就是說我們不用分組了，車輛相關的耗損和營收記錄都冗余到了車輛信息記錄中，那么接下來就是對數組中的某一字段或者多個進行求和了……查了半天並沒有找到類似$sum這樣的聚合管道可以對數組中的字段求和，不過得益於mongodb管道的強大，用另外一個管道間接實現了這個功能。

db.getCollection('FormInstace').aggregate([
    {
        $match: {
            "_id": { $in: ["1","2","3"] },
            "FormItems.key": { $ne: null }
        }
    },
    {
        $addFields: {
            FormValueObj: {
                $arrayToObject: {
                    $map: {
                        input: "$FormItems",
                        as: "field",
                        in: [ "$$field.key", "$$field.value" ]
                    }
                }
            }
        }
    },
    {
      $replaceRoot: { newRoot: { $mergeObjects: [ "$FormValueObj", "$$ROOT" ] } }
    },
    {
        $project: {
            FormItems:0,
            FormValueObj:0
        }
    },
    {   
        $lookup:{
            from:"FormInstace",
            let: { tempMainRelationKey: "$_id" },
            pipeline:[
                {
                    $match: { 
                        FormId: "507048044944692000",
                        "FormItems.key": { $ne: null }                        
                    }
                },
                {
                    $addFields: {
                        FormValueObj: {
                            $arrayToObject: {
                                $map: {
                                    input: "$FormItems",
                                    as: "field",
                                    in: [ "$$field.key", "$$field.value" ]
                                }
                            }
                        }
                    }
                },
                {
                  $replaceRoot: { newRoot: { $mergeObjects: [ "$FormValueObj", "$$ROOT" ] } }
                },
                {
                    $project: {
                        FormItems:0,
                        FormValueObj:0
                    }
                },
                { $match:
                     { $expr:
                            { $eq: [ "$1572493552001.id","$$tempMainRelationKey" ] }
                     }
                },
            ],
            as:'carWastage'
        }
    },
    {   
        $lookup:{
            from:"FormInstace",
            let: { tempMainRelationKey: "$_id" },
            pipeline:[
                {
                    $match: { 
                        FormId: "507048044944693000",
                        "FormItems.key": { $ne: null }                        
                    }
                },
                {
                    $addFields: {
                        FormValueObj: {
                            $arrayToObject: {
                                $map: {
                                    input: "$FormItems",
                                    as: "field",
                                    in: [ "$$field.key", "$$field.value" ]
                                }
                            }
                        }
                    }
                },
                {
                  $replaceRoot: { newRoot: { $mergeObjects: [ "$FormValueObj", "$$ROOT" ] } }
                },
                {
                    $project: {
                        FormItems:0,
                        FormValueObj:0
                    }
                },
                { $match:
                     { $expr:
                            { $eq: [ "$1572493553001.id","$$tempMainRelationKey" ] }
                     }
                },
            ],
            as:'carRevenue'
        }
    },
    {
        $addFields: {
            carWastageStatistics: {
               $reduce: {
                  input: "$carWastage",
                  initialValue: {wastageMoney:0},
                  in: {
                      wastageMoney:{ $add : ["$$value.wastageMoney", "$$this.1572493552005"] }
                  }
               }
            }
        }
    },
    {
        $addFields: {
            carRevenueStatistics: {
               $reduce: {
                  input: "$carRevenue",
                  initialValue: {revenueMoney:0,mileage:0},
                  in: { 
                    revenueMoney:{$add : ["$$value.revenueMoney", "$$this.1572493553005"]},
                    mileage:{$add : ["$$value.mileage", "$$this.1572493553006"]}
                  }
               }
            }
        }
    }
]);

　　這次統計查詢就查出了某些車輛的總耗損金額和總營收金額、總里程數；只不過將結果放到對象中了（方便統計一個表中的多個字段），但是現在看不到具體的結果，將代碼在修改一下，看一下結果

db.getCollection('FormInstace').aggregate([
    {
        $match: {
            "_id": { $in: ["1","2","3"] },
            "FormItems.key": { $ne: null }
        }
    },
    {
        $addFields: {
            FormValueObj: {
                $arrayToObject: {
                    $map: {
                        input: "$FormItems",
                        as: "field",
                        in: [ "$$field.key", "$$field.value" ]
                    }
                }
            }
        }
    },
    {
      $replaceRoot: { newRoot: { $mergeObjects: [ "$FormValueObj", "$$ROOT" ] } }
    },
    {
        $project: {
            FormItems:0,
            FormValueObj:0
        }
    },
    {   
        $lookup:{
            from:"FormInstace",
            let: { tempMainRelationKey: "$_id" },
            pipeline:[
                {
                    $match: { 
                        FormId: "507048044944692000",
                        "FormItems.key": { $ne: null }                        
                    }
                },
                {
                    $addFields: {
                        FormValueObj: {
                            $arrayToObject: {
                                $map: {
                                    input: "$FormItems",
                                    as: "field",
                                    in: [ "$$field.key", "$$field.value" ]
                                }
                            }
                        }
                    }
                },
                {
                  $replaceRoot: { newRoot: { $mergeObjects: [ "$FormValueObj", "$$ROOT" ] } }
                },
                {
                    $project: {
                        FormItems:0,
                        FormValueObj:0
                    }
                },
                { $match:
                     { $expr:
                            { $eq: [ "$1572493552001.id","$$tempMainRelationKey" ] }
                     }
                },
            ],
            as:'carWastage'
        }
    },
    {   
        $lookup:{
            from:"FormInstace",
            let: { tempMainRelationKey: "$_id" },
            pipeline:[
                {
                    $match: { 
                        FormId: "507048044944693000",
                        "FormItems.key": { $ne: null }                        
                    }
                },
                {
                    $addFields: {
                        FormValueObj: {
                            $arrayToObject: {
                                $map: {
                                    input: "$FormItems",
                                    as: "field",
                                    in: [ "$$field.key", "$$field.value" ]
                                }
                            }
                        }
                    }
                },
                {
                  $replaceRoot: { newRoot: { $mergeObjects: [ "$FormValueObj", "$$ROOT" ] } }
                },
                {
                    $project: {
                        FormItems:0,
                        FormValueObj:0
                    }
                },
                { $match:
                     { $expr:
                            { $eq: [ "$1572493553001.id","$$tempMainRelationKey" ] }
                     }
                },
            ],
            as:'carRevenue'
        }
    },
    {
        $addFields: {
            carWastage_Money: {
               $reduce: {
                  input: "$carWastage",
                  initialValue: 0,
                  in: { $add : ["$$value", "$$this.1572493552005"] }
               }
            }
        }
    },
    {
        $addFields: {
            carRevenue_Money: {
               $reduce: {
                  input: "$carRevenue",
                  initialValue: 0,
                  in: { $add : ["$$value", "$$this.1572493553005"] }
               }
            }
        }
    },
    {
        $addFields: {
            carRevenue_Mileage: {
               $reduce: {
                  input: "$carRevenue",
                  initialValue: 0,
                  in: { $add : ["$$value", "$$this.1572493553006"] }
               }
            }
        }
    }
]);

　　這樣就一目了然了。統計結果對不對呢？我們用傳統的分組之后再求和在查詢一下，將結果做一下對比（順便記錄一下，分組求和）

db.getCollection('FormInstace').aggregate([
    {
        $match: {
            "FormId":"507048044944692000",
            "FormItems.key": { $ne: null }
        }
    },
    {
        $addFields: {
            FormValueObj: {
                $arrayToObject: {
                    $map: {
                        input: "$FormItems",
                        as: "field",
                        in: [ "$$field.key", "$$field.value" ]
                    }
                }
            }
        }
    },
    {
        $replaceRoot: { newRoot: { $mergeObjects: [ "$FormValueObj", "$$ROOT" ] } }
    },
    {
        $match: {
            "1572493552001.id": { $in:["1","2","3"]}
        }
    },
    {
        $project: {
            FormItems:0,
            FormValueObj:0
        }
    },
    {
        $group:{
           _id: "$1572493552001.id",
           wastageMoney: { $sum: "$1572493552005"}
        }
    },
    { $sort : { _id: 1 } }
]);

db.getCollection('FormInstace').aggregate([
    {
        $match: {
            "FormId":"507048044944693000",
            "FormItems.key": { $ne: null }
        }
    },
    {
        $addFields: {
            FormValueObj: {
                $arrayToObject: {
                    $map: {
                        input: "$FormItems",
                        as: "field",
                        in: [ "$$field.key", "$$field.value" ]
                    }
                }
            }
        }
    },
    {
        $replaceRoot: { newRoot: { $mergeObjects: [ "$FormValueObj", "$$ROOT" ] } }
    },
    {
        $match: {
            "1572493553001.id": { $in:["1","2","3"]}
        }
    },
    {
        $project: {
            FormItems:0,
            FormValueObj:0
        }
    },
    {
        $group:{
           _id: "$1572493553001.id",
           wastageMoney: { $sum: "$1572493553005"},
           mileage: { $sum: "$1572493553006"}
        }
    },
    { $sort : { _id: 1 } }
]);

　　對比兩次查詢結果，兩次不同的統計方式的結果相同。這樣就放心了。好了就到這里了。

　　********************以下是修改補充部分********************

　　打臉了，好疼，┭┮﹏┭┮……曾記得以前使用$sum對數組中的某一屬性求和時沒有得到預期的結果，這篇筆記寫完之后，打算在按照常規思路（$unwind、$group、$sum等）在寫一種查詢方式，但是但是但是測試的時候發現$sum好使了，寫放一下代碼

db.getCollection('FormInstace').aggregate([
    {
        $match: {
            "_id": { $in: ["1","2","3"] },
            "FormItems.key": { $ne: null }
        }
    },
    {
        $addFields: {
            FormValueObj: {
                $arrayToObject: {
                    $map: {
                        input: "$FormItems",
                        as: "field",
                        in: [ "$$field.key", "$$field.value" ]
                    }
                }
            }
        }
    },
    {
      $replaceRoot: { newRoot: { $mergeObjects: [ "$FormValueObj", "$$ROOT" ] } }
    },
    {
        $project: {
            FormItems:0,
            FormValueObj:0
        }
    },
    {   
        $lookup:{
            from:"FormInstace",
            let: { tempMainRelationKey: "$_id" },
            pipeline:[
                {
                    $match: { 
                        FormId: "507048044944692000",
                        "FormItems.key": { $ne: null }                        
                    }
                },
                {
                    $addFields: {
                        FormValueObj: {
                            $arrayToObject: {
                                $map: {
                                    input: "$FormItems",
                                    as: "field",
                                    in: [ "$$field.key", "$$field.value" ]
                                }
                            }
                        }
                    }
                },
                {
                  $replaceRoot: { newRoot: { $mergeObjects: [ "$FormValueObj", "$$ROOT" ] } }
                },
                {
                    $project: {
                        FormItems:0,
                        FormValueObj:0
                    }
                },
                { $match:
                     { $expr:
                            { $eq: [ "$1572493552001.id","$$tempMainRelationKey" ] }
                     }
                },
            ],
            as:'carWastage'
        }
    },
    {   
        $lookup:{
            from:"FormInstace",
            let: { tempMainRelationKey: "$_id" },
            pipeline:[
                {
                    $match: { 
                        FormId: "507048044944693000",
                        "FormItems.key": { $ne: null }                        
                    }
                },
                {
                    $addFields: {
                        FormValueObj: {
                            $arrayToObject: {
                                $map: {
                                    input: "$FormItems",
                                    as: "field",
                                    in: [ "$$field.key", "$$field.value" ]
                                }
                            }
                        }
                    }
                },
                {
                  $replaceRoot: { newRoot: { $mergeObjects: [ "$FormValueObj", "$$ROOT" ] } }
                },
                {
                    $project: {
                        FormItems:0,
                        FormValueObj:0
                    }
                },
                { $match:
                     { $expr:
                            { $eq: [ "$1572493553001.id","$$tempMainRelationKey" ] }
                     }
                },
            ],
            as:'carRevenue'
        }
    },
    {
        $addFields: {
            "carWastageStatistics.wastageMoney": { $sum: "$carWastage.1572493552005"},
            "carRevenueStatistics.revenueMoney": { $sum: "$carRevenue.1572493553005"},
            "carRevenueStatistics.mileage": { $sum: "$carRevenue.1572493553006"}
        }
    }
]);

db.getCollection('FormInstace').aggregate([
    {
        $match: {
            "_id": { $in: ["1","2","3"] },
            "FormItems.key": { $ne: null }
        }
    },
    {
        $addFields: {
            FormValueObj: {
                $arrayToObject: {
                    $map: {
                        input: "$FormItems",
                        as: "field",
                        in: [ "$$field.key", "$$field.value" ]
                    }
                }
            }
        }
    },
    {
      $replaceRoot: { newRoot: { $mergeObjects: [ "$FormValueObj", "$$ROOT" ] } }
    },
    {
        $project: {
            FormItems:0,
            FormValueObj:0
        }
    },
    {   
        $lookup:{
            from:"FormInstace",
            let: { tempMainRelationKey: "$_id" },
            pipeline:[
                {
                    $match: { 
                        FormId: "507048044944692000",
                        "FormItems.key": { $ne: null }                        
                    }
                },
                {
                    $addFields: {
                        FormValueObj: {
                            $arrayToObject: {
                                $map: {
                                    input: "$FormItems",
                                    as: "field",
                                    in: [ "$$field.key", "$$field.value" ]
                                }
                            }
                        }
                    }
                },
                {
                  $replaceRoot: { newRoot: { $mergeObjects: [ "$FormValueObj", "$$ROOT" ] } }
                },
                {
                    $project: {
                        FormItems:0,
                        FormValueObj:0
                    }
                },
                { $match:
                     { $expr:
                            { $eq: [ "$1572493552001.id","$$tempMainRelationKey" ] }
                     }
                },
            ],
            as:'carWastage'
        }
    },
    {   
        $lookup:{
            from:"FormInstace",
            let: { tempMainRelationKey: "$_id" },
            pipeline:[
                {
                    $match: { 
                        FormId: "507048044944693000",
                        "FormItems.key": { $ne: null }                        
                    }
                },
                {
                    $addFields: {
                        FormValueObj: {
                            $arrayToObject: {
                                $map: {
                                    input: "$FormItems",
                                    as: "field",
                                    in: [ "$$field.key", "$$field.value" ]
                                }
                            }
                        }
                    }
                },
                {
                  $replaceRoot: { newRoot: { $mergeObjects: [ "$FormValueObj", "$$ROOT" ] } }
                },
                {
                    $project: {
                        FormItems:0,
                        FormValueObj:0
                    }
                },
                { $match:
                     { $expr:
                            { $eq: [ "$1572493553001.id","$$tempMainRelationKey" ] }
                     }
                },
            ],
            as:'carRevenue'
        }
    },
    {
        $addFields: {
            "carWastage_Money": { $sum: "$carWastage.1572493552005"},
            "carRevenue_Money": { $sum: "$carRevenue.1572493553005"},
            "carRevenue_Mileage": { $sum: "$carRevenue.1572493553006"},
        }
    }
]);

　　下面看一下對比圖，看一下改動情況

　　再看一下，執行結果截圖

 

　　和上面的結果一模一樣……對mongodb管道認識不夠深入，應用中有需求就是查一下，太片面了，沒有驗證的東西千萬別亂說，切記切記切記！！！特尷尬，￣□￣｜｜