问题描述
我有一个 MERN 堆栈应用程序,当我进行 GET 调用时,我想返回我所有 MongoDB 对象的投票。
这就是我的对象的样子:
{_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"),ranking: 1
]}
显然会有更多数据,但基本上我希望它返回:
[{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!
解决方法
-
$unwind
解构movies
数组 -
$group
bymovies.title
和 sumranking
let result = await YourModelName.aggregate([ // replace your model name
{ $unwind: "$movies" },{
$group: {
_id: "$movies.title",ranking: { $sum: "$movies.ranking" }
}
}
])