mongoDB，带有 $sum 和 $count 的 mongoose 聚合查询

Question

世界！ 我是 mongodb 的新手，我不知道我可以通过聚合和求和等来完成这项任务..( 所以，我有这个系列： 这是商店集合

{
"storeName": "store one",
"_id" : ObjectId("store id 1"), // this is store ID
"shopId" : ObjectId("shopId 1"),
"shopItems" : [
    {
        "_id" : ObjectId("6048a1fa31d779032b16301e"),
        "itemId" : ObjectId("111"), // this is product id from PRODUCTS collection
        "itemCount" : 2
    },
    {
        "_id" : ObjectId("6048a46e31d779032b163043"),
        "itemId" : ObjectId("222"),// this is product id from PRODUCTS collection
        "itemCount" : 0
    }
  ],
},
{
   "storeName": "store two"
   "_id" : ObjectId("storeId 2"), // this is store ID
   "shopId" : ObjectId("shopId 2"),
   "shopItems" : [
    {
        "_id" : ObjectId("6048a1fa31d779032b16301e"),
        "itemId" : ObjectId("222"), // this is product id from PRODUCTS collection
        "itemCount" : 2
    },
    {
        "_id" : ObjectId("6048a46e31d779032b163043"),
        "itemId" : ObjectId("333"),// this is product id from PRODUCTS collection
        "itemCount" : -5
    }
            {
        "_id" : ObjectId("6048a46e31d779032b163043"),
        "itemId" : ObjectId("111"),// this is product id from PRODUCTS collection
        "itemCount" : -7
    }
  ],
}

这是产品集合，这是一个不同价格的数组， 实际上还有更多〜50/50。我收集了 boolean 表示商店的价格 是不同的（也许对任务有帮助）

// products collection
{
    "_id" : ObjectId("111"), // itemId in STORE collection
    "differentPricesForShops" : false,
    "productName" : "some name here",
    "buyPrice" : 10,
    "sellingPrice" : 100,
    "differentPricesForShops" : false,
    "difPriceArray" : []
},
{
    "_id" : ObjectId("222"), // itemId in STORE collection
    "differentPricesForShops" : false,
    "productName" : "some name here",
    "differentPricesForShops" : true, <- TRUE
    "difPriceArray" : [
        {
            "shopId": ObjectId("shopId1") <- shop
            "buyPrice" : 5,   <- differentPrices
            "sellingPrice" : 50,
        },
        {
            "shopId": ObjectId("shopId 2")
            "buyPrice" : 15,
            "sellingPrice" : 55,
        },
    ]
},
{
    "_id" : ObjectId("333"), // itemId in STORE collection
    "differentPricesForShops" : false,
    "productName" : "some name here",
    "buyPrice" : 5,
    "sellingPrice" : 15,
    "differentPricesForShops" : false,
    "difPriceArray" : []
},

我需要这个输出数据：

"shopId" : ObjectId("6048a15031d779032b16300f"),

产品数量：2，

产品负数：0，

selfprice: (2-> 店内计数 * 10(buyPrice) ) = 20

待售产品：（2 -> 店内数量 * 100（售价））= 200

---

"shopId" : ObjectId("6048a15031d779032b16300f"),

产品数量：2，

减号产品：-5（店内商品数）+ -7（店内商品数）= -12

selfprice：（2-> 店内数 * 15（不同店价））= 30

待售产品：（2 -> 店内数量 * 55（各店价格不同））= 110

---

这个例子是按 1 个产品，但 我需要有 selfPrice 和待售产品的总和。 请检查图片 我需要这样显示数据：

data in table img

我希望有人可以帮助我。非常感谢！

Answer 1

此聚合查询将为您提供所需的输出：

管道阶段：

1. unwind : 这将为给定商店的每个产品创建单独的文档

2. lookup : 这将用于连接和获取产品详细信息

3. unwind : 因为查找结果是数组，所以将它作为文档/对象

4. addfields：检查价格是否存在差异，然后设置适当的值

5. addfields：将上述步骤中匹配的商店 $buyPrice 和 $ sellPrice 从对象转换为字段

6. addfields：根据上述步骤中的 $buyPrice 和 $ sellPrice 设置 selfprice 和 products_for_sale

7. 组：以我们想要的方式提取字段！

     [{$unwind: {
          path: '$shopItems' 
        }}, {$lookup: {
          from: 'products',
          localField: 'shopItems.itemId',
          foreignField: '_id',
          as: 'shop_products'
        }}, {$unwind: {
          path: '$shop_products'
   
        }}, {$addFields: {
          buyPrice:{  $cond: { if:{ $anyElementTrue:["$shop_products.difPriceArray"]}, 
          then:{
                     $arrayElemAt:[{$filter: {
                       input: "$shop_products.difPriceArray",
                       as: "item",
                       cond: { $eq: [ "$$item.shopId", '$shopId' ] }
                    }
                 },0]}
              , 
          else: '$shop_products.buyPrice'}},
          sellingPrice:{  $cond: { if:{ $anyElementTrue:["$shop_products.difPriceArray"]}, 
          then:{
                     $arrayElemAt:[{$filter: {
                       input: "$shop_products.difPriceArray",
                       as: "item",
                       cond: { $eq: [ "$$item.shopId", '$shopId' ] }
                    }
                 },0]}, 
   
   
              else: '$shop_products.sellingPrice'}},
        }}, {$addFields: {
          buyPrice: {  $cond: { if:{ $eq: [{$type: '$buyPrice'},"object"] }, then: '$buyPrice.buyPrice' ,else:'$buyPrice'}},
          sellingPrice: {  $cond: { if:{ $eq: [{$type: '$sellingPrice'},"object"] }, then: '$sellingPrice.sellingPrice' ,else:'$sellingPrice'}}
        }}, {$addFields: {
        selfprice: { $multiply: [ {$ifNull:['$shopItems.itemCount',0]}, {$ifNull:[ '$buyPrice',0]}] },
        products_for_sale  :{ $multiply: [ {$ifNull:['$shopItems.itemCount',0]}, {$ifNull:[ '$sellingPrice',0]}] },
   
        }}, {$group: {
          _id: '$_id',
          selfprice:{$sum: {
                         $cond: { if: { $lt: [ "$selfprice", 0 ] }, then: 0, else: '$selfprice' } 
                       }},
          product_count:{$sum:1},
          shopId:{$first:'$shopId'},
          product_in_minus:{$sum: {
                         $cond: { if: { $lt: [ "$shopItems.itemCount", 0 ] }, then: "$shopItems.itemCount", else: 0 }
                       }} ,
          products_for_sale:{$sum: {
                         $cond: { if: { $lt: [ "$products_for_sale", 0 ] }, then: 0, else: '$products_for_sale' } 
                       }} 
        }}]
   

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