mongoDB, mongoose 聚合查询 $sum 和 $count

Question

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

{
"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 collection，这是一组 不同价格，事实上还有更多~50/50。我在 collection 中有 boolean 那就是说如果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，

负乘积: 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，

产品减：-5（店内商品数）+ -7（店内商品数）= -12

selfprice: (2-> store count * 15(不同店铺价格不同) ) = 30

待售产品：（2 -> 店内数量 * 55（不同店铺价格不同））= 110

此示例是 by 1 product，但是我需要 SUM 的 selfPrices 和待售产品。 请检查图片 我需要这样显示数据：

data in table img

我希望有人能帮助我。非常感谢！

Answer 1

此聚合查询将为您提供所需的输出：

流水线阶段：

unwind：这将为给定商店的每个产品创建单独的文档
查找：这将用于加入和获取产品详细信息
unwind : 因为查找结果是数组，所以它会变成 document/object
addfields：检查价格是否存在差异然后设置适当的值
addfields：将上述步骤中匹配的商店 $buyPrice 和 $sellingPrice 从对象转换为字段
addfields：根据上述步骤
根据 $buyPrice 和 $sellingPrice 设置 selfprice & products_for_sale

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' } 
                    }} 
     }}]

Mongo 游乐场：https://mongoplayground.net/p/P7xYYEQBJ-J

mongoDB, mongoose 聚合查询 $sum 和 $count

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我需要这个输出数据：