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欄位當中。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,可能我們更關註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麼得到這些數據。要想獲取這些記錄我們首先想到的就是先按 ...
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欄位當中。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,可能我們更關註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麼得到這些數據。要想獲取這些記錄我們首先想到的就是先按照車輛ID分組之後再對指定欄位求和,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,而是想著看看能不能在上一篇筆記的基礎之上得到想要的結果。
我們沿著這條路在分析一下,車輛相關的耗損和營收都可以放到一個欄位中。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餘到了車輛信息記錄中,那麼接下來就是對數組中的某一欄位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欄位求和,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", "$$this.1572493553006"]} } } } } } ]);
這次統計查詢就查出了某些車輛的總耗損金額和總營收金額、總里程數;只不過將結果放到對象中了(方便統計一個表中的多個欄位),但是現在看不到具體的結果,將代碼在修改一下,看一下結果
db.getCollection('FormInstace').aggregate([ { $match: { "_id": { $in: ["1","2","3"] }, "FormItems.key": { $ne: null } } }, { $addFields: { FormValueObj: { $arrayToObject: { $map: { input: "$FormItems", as: "field", in: [ "$$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"] } } } } } ]);
這樣就一目瞭然了。統計結果對不對呢?我們用傳統的分組之後再求和在查詢一下,將結果做一下對比(順便記錄一下,分組求和)
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
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", "$$ROOT" ] } } }, { $match: { "1572493552001.id": { $in:["1","2","3"]} } }, { $project: { FormItems:0, FormValueObj:0 } }, { $group:{ _id: "$1572493552001.id", wastageMoney: { $sum: "$1572493552005"} } }, { $sort : { _id: 1 } } ]);統計指定車輛的耗損總額
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
db.getCollection('FormInstace').aggregate([ { $match: { "FormId":"507048044944693000", "FormItems.key": { $ne: null } } }, { $addFields: { FormValueObj: { $arrayToObject: { $map: { input: "$FormItems", as: "field", in: [ "$$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"} } }, { $sort : { _id: 1 } } ]);統計指定車輛的營收總額和里程數
對比兩次查詢結果,兩次不同的統計方式的結果相同。這樣就放心了。好了就到這裡了。
********************以下是修改補充部分********************
打臉了,好疼,┭┮﹏┭┮……曾記得以前使用$sum對數組中的某一屬性求和時沒有得到預期的結果,這篇筆記寫完之後,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
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
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","$$tempMainRelationKey" ] } } }, ], as:'carRevenue' } }, { $addFields: { "carWastageStatistics.wastageMoney": { $sum: "$carWastage.1572493552005"}, "carRevenueStatistics.revenueMoney": { $sum: "$carRevenue.1572493553005"}, "carRevenueStatistics.mileage": { $sum: "$carRevenue.1572493553006"} } } ]);在文中第一個查詢語句基礎上修改
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
db.getCollection('FormInstace').aggregate([ { $match: { "_id": { $in: ["1","2","3"] }, "FormItems.key": { $ne: null } } }, { $addFields: { FormValueObj: { $arrayToObject: { $map: { input: "$FormItems", as: "field", in: [ "$$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"}, } } ]);在文中第二個查詢語句基礎上修改
下麵看一下對比圖,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, ̄□ ̄||