javascript - 如何过滤取自 $lookup 的数据

Question

我目前正在尝试通过使用获取的数据过滤它们来聚合文档列表$lookup

Product.aggregate([
{
        $lookup: {
          from: "categories",
          localField: "category",
          foreignField: "_id",
          as: "category",
        },
      },
      { $unwind: "$category" }])

我希望添加{ $match: { "category.left": {$gte: 3}} },能够获得left属性大于指定类别的所有产品，但到目前为止我什么也没得到。解决方案是什么？

分类文件

{ "_id" : ObjectId("570557d4094a4514fc1291d6"), "left" : 1, "right" : "2" }
{ "_id" : ObjectId("570557d4094a4514fc1291d7"), "left" : 3, "right" : "8"}
{ "_id" : ObjectId("570557d4094a4514fc1291d8"), "left" : 4, "right" : "5"}
{ "_id" : ObjectId("570557d4094a4514fc1291d9"), "left" : 6, "right" : "7" }

产品文件

{ "_id" : ObjectId("570557d4094a4514fc129120"), "category": ObjectId("570557d4094a4514fc1291d6") }
{ "_id" : ObjectId("570557d4094a4514fc129121"), "category": ObjectId("570557d4094a4514fc1291d7")}
{ "_id" : ObjectId("570557d4094a4514fc129122"), "category": ObjectId("570557d4094a4514fc1291d8")}
{ "_id" : ObjectId("570557d4094a4514fc129123"), "category": ObjectId("570557d4094a4514fc1291d9") }

我期待得到

{ "_id" : ObjectId("570557d4094a4514fc129121"), "category": ObjectId("570557d4094a4514fc1291d7")}
{ "_id" : ObjectId("570557d4094a4514fc129122"), "category": ObjectId("570557d4094a4514fc1291d8")}
{ "_id" : ObjectId("570557d4094a4514fc129123"), "category": ObjectId("570557d4094a4514fc1291d9") }

对于我的回应

标签： javascriptnode.jsmongodb