上一篇笔记仅是记录了一下简单的关联查询,根据笔记中的场景:将某一车辆关联的耗损记录全部放在了一个字段当中。不知道现在中有没有这种场景,我们的应用中没有类似的场景,可能我们更关注的是某车辆的总耗损金额和总营收金额、总里程数等,因此这篇笔记记录一下怎么得到这些数据。要想获取这些记录我们首先想到的就是先按照车辆ID分组之后再对指定字段求和,可能是先入为主的原因(有了上一篇笔记),我没有按照传统的思路走下去,而是想着看看能不能在上一篇笔记的基础之上得到想要的结果。
我们沿着这条路在分析一下,车辆相关的耗损和营收都可以放到一个字段中。也就是说我们不用分组了,车辆相关的耗损和营收记录都冗余到了车辆信息记录中,那么接下来就是对数组中的某一字段或者多个进行求和了……查了半天并没有找到类似$sum这样的聚合管道可以对数组中的字段求和,不过得益于mongodb管道的强大,用另外一个管道间接实现了这个功能。
- 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"]}
- }
- }
- }
- }
- }
- ]);

这次统计查询就查出了某些车辆的总耗损金额和总营收金额、总里程数;只不过将结果放到对象中了(方便统计一个表中的多个字段),但是现在看不到具体的结果,将代码在修改一下,看一下结果
- 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"] }
- }
- }
- }
- }
- ]);

这样就一目了然了。统计结果对不对呢?我们用传统的分组之后再求和在查询一下,将结果做一下对比(顺便记录一下,分组求和)

- 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 } }
- ]);
统计指定车辆的耗损总额

- 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 } }
- ]);
统计指定车辆的营收总额和里程数

对比两次查询结果,两次不同的统计方式的结果相同。这样就放心了。好了就到这里了。