需要帮助聚合猫鼬数据

Question

我有一个 MERN 堆栈应用程序，当我进行 GET 调用时，我想 return 我所有 MongoDB 对象的投票。

这是我的对象的样子：

{_id: ObjectId("6092d48d96984d233cf77152")
user: "John Doe"
movies: [
     0:
          _id: ObjectId("6092b19345f48a33447468a7"),
          title: "Alpha",
          ranking: 3
     1:
          _id: ObjectId("6092b19345f48a33447468a7"),
          title: "Bravo",
          ranking: 2
     2:
          _id: ObjectId("6092b19345f48a33447468a7"),
          title: "Charlie",
          ranking: 1
]}

{_id: ObjectId("6092d48d96984d233cf77152")
user: "John Doe"
movies: [
     0:
          _id: ObjectId("6092b19345f48a33447468a7"),
          title: "Alpha",
          ranking: 3
     1:
          _id: ObjectId("6092b19345f48a33447468a7"),
          title: "Bravo",
          ranking: 2
     2:
          _id: ObjectId("6092b19345f48a33447468a7"),
          title: "Charlie",
          ranking: 1
]}

显然会有更多数据，但基本上我希望它 return:

[{title: "Alpha", ranking: 6},
{title: "Bravo", ranking: 4},
{title: "Charlie", ranking: 2}]

我假设我必须使用 $match 函数，但这是我第一次像这样使用 Mongoose/MongoDB。提前致谢！

Answer 1

$unwind解构movies数组
$group 乘以 movies.title 并求和 ranking

let result = await YourModelName.aggregate([ // replace your model name
  { $unwind: "$movies" },
  {
    $group: {
      _id: "$movies.title",
      ranking: { $sum: "$movies.ranking" }
    }
  }
])

Playground

需要帮助聚合猫鼬数据

Need help aggregating mongoose data

mongoose

mongodb

aggregation-framework

mern