具有对象数组的Mongo DB聚合 [英] Mongo DB aggregation with array of objects

问题描述

我的收集模式如下:

产品

{
  _id: ObjectId(), // default mongo db id
  specification: [
    {key: 'Name', value: "value 1"},
    {key: 'Category', value: "value 2"},
    {key: 'Department', value: "value 3"}
  ]
}

现在，我想使用通用过滤器对此进行查询.例如

Now I want to query on this with a generic filter. For example,

1. 让我使用Name = value 1和Category in [value 2, value 3]和Department = value 3
获得所有产品
2. 使用Name = value 1或Category = value 2或Department in [value 3, value 4]
给我所有产品

1. Get me all product with Name = value 1 and Category in [value 2, value 3] and Department = value 3
2. Get me all product with Name = value 1 or Category = value 2 or Department in [value 3, value 4]

我一直在尝试将$match与$elemMatch一起使用.但这仅允许一个查询，但是我不能使用$and和$or运算符.

I have been trying to use $match with $elemMatch. But that only allows only one query but I am not able to use the $and and $or operator.

推荐答案

您可以很好地使用$elemMatch，只需将$and/$or放在最顶层即可.

You can use $elemMatch just fine, you just have to put $and / $or at the top level.

您的第一个示例是

db.products.find({
  $and: [
    { 
      specification: {
        $elemMatch: { key: 'Name', value: 'value 1' }
      }
    },
    {
      specification: {
        $elemMatch: { key: 'Category', value: { $in: ['value 1', 'value 2'] } }
      }
    },
    { 
      specification: {
        $elemMatch: { key: 'Department', value: 'value 3' }
      }
    }
  ]
})

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